Starting a Warlock

Introduction
A Warlock is an arcane spellcaster, similar to a Wizard, but with a few key differences:
 * A Warlock learns spells instinctively, unlike a wizard that learns by studying.
 * A Warlock's spells are powered by his/her Charisma.
 * A Warlock can use Eldritch Blast without spending spell points.

Warlocks are proficient with simple weapons, and can wear cloth or light armor without risking Arcane Spell Failure. Heavier armor incurs a chance of arcane spell failure. Warlocks have great melee and ranged capabilities. They can transform their eldritch blasts into forms that bounce damage from enemy to enemy or do serious area of effect damage (cone-shaped, point blank area of effect over time, or point blank area of effect burst damage) Back row or not, the sheer amount of death you are dealing will cause the mobs to aggro on you fast and concentrate fire on you. To deal with this you should:
 * Kill them before they can attack/significantly damage you. This is the Warlock's preferred method.
 * Crowd Control them while you kill them. Focusing in enchantment spells also works wonders in keeping the mobs off of you while you fight.
 * If all else fails, have resistances and immunities to live long enough to finish the fight. Spells like blur and displacement help, and careful selection of items that make you more durable.

Overall compared to other spellcasting classes, a Warlock may not be able to do as much quick-burst damage as a Wizard or Sorcerer from single, heavy spell casts, but as spellcasters go a Warlock can be made EXCEPTIONALLY endurant, both in defenses and ability to put out constant, sustained damage to entire squads of enemies at once without quickly depleting their SP pool. They can also very easily get a very high UMD rating allowing for a great deal of tactical flexibility from properly selected wands and scrolls.

Specific Pointers
Your Charisma fuels your spells. It dictates how strong your spells are and how many bonus Spell Points (SP) you get. A couple races are a more suitable choice for your Warlock. Human is possibly the best starting point as they get the Human Adaptability enhancement to add to their Charisma. Drow Elves, and Half-Elves are also good choices for a Warlock.

Elves get arcane spell failure reduction enhancements. Drow get a bonus to Charisma allowing them to start with a score of 20, and increase it via enhancements to 22. No other race can match that (although humans can hit it temporarily via power boosts, and take a bonus feat that powers the DC up permanently as well). The intelligence bonus helps them match humans in skill points as well. The constitution penalty is notable, but can be worked around.

Other options: Although Aasimar cannot have their warlock pact and aasimar pact active at the same time, aasimar can increase their charisma by 2 points through the aasimar racial enhancement tree. Although sun elves would need a +1 heart of wood to be a single-class warlock, the sun elf racial enhancement tree can add +30 radiance spell power, which can be useful for warlocks focusing on the Eldritch Burst and Spiritual Retribution enhancements in the Enlightened Spirit enhancement tree.

Another tip: 1 point in tumble at level 1 helps you tumble out of the way of ray spells. This has an added benefit of slightly reducing your damage from falls. Add skill points to use magic device, spellcraft, and concentration. Additionally, adding points of Perform unlocks perform bonuses to be added to sonic spellpower which is helpful if you selected the Fey Pact.

Attributes

 * Strength is a non-essential stat for Warlocks. The main draw of increasing strength is to offset the possibility of strength-sapping effects, like Ray of Enfeeblement, Ray of Exhaustion which can leave you helpless and unable to cast spells.
 * Dexterity helps a Warlock to avoid being hit in melee combat by any of the many enemies who may become enraged by your damaging spells and charge past the melee combatants to attack you. It also helps to protect you from becoming helpless from Ability Damaged to Dexterity. The Armor Class bonus from Dexterity soon becomes irrelevant as you tackle higher level monsters, but the bonus to Reflex Save is considered by some to be valuable. However, as Intelligence is generally more important for a Warlock to raise than Dexterity, Insightful Reflexes is worth considering.
 * Constitution is always helpful for any character. More Constitution equates to more hit points, and a higher Fortitude save. Constitution should (nearly always) be your second highest stat and in warlocks should be no lower than 16 (except on elves and drow where 14 is the best they can do). Some aura warlocks can make Constitution their primary stat.
 * Intelligence affects the number of Warlocks skill points. Warlocks should allocate skill points to spellcraft and Use Magic Device. Concentration is helpful for casting spells and scrolls. Perform is good for Warlocks with the Fey Pact.
 * Wisdom affects a Warlock's Will save. Will Save can be greatly increased by taking the Force of Personality feat and makes Wisdom much less important for a Warlock to train; the only remaining uses being boosting a few skills, operating a Wisdom-based Rune switch in quests and preventing becoming Helpless from stat-draining attacks.
 * Charisma affects a Warlock's casting ability. Higher Charisma leads to higher spell point totals and higher DCs for the spells you cast. The great majority of Warlocks start with 18 or 20 Charisma and increase it as they level up and obtain charisma gear. (20 is only available to Drow, Tiefling  and Dragonborn and 16 is the maximum available to Warforged  Half-Orc  and Dwarves.)

Feats
Warlocks get special Warlock bonus feats at character creation and as they level, see Advancement table.

Feats many warlocks find useful include (somewhat in order of importance). Note that metamagics do NOT work on Eldritch Blasts of any shape (blast, cone, chain, aura) but can be applied for free to any of the many SLAs available, including the bursts.


 * Spell Focus: Evocation - This helps overcome enemy saves to the Pact damage of Eldritch Blast.
 * Greater Spell Focus: Evocation - This also helps overcome enemy saves to the Pact damage of Eldritch Blast.
 * Mental Toughness - More spell points, a 1% increase in spell crits (affects Eldritch Blast), and unlocks epic mental toughness.
 * Improved Mental Toughness - More spell points, a 1% increase in spell crits (affects Eldritch Blast).
 * Epic Mental Toughness 200 spell points and a 1% increase in spell crits (affects Eldritch Blast).
 * Quicken Spell - Increases spell point cost and allows you to cast a little more quickly, with no chance of interruption.
 * Maximize Spell - Increases spellpower by 150 at a cost of 25 SP per spell. Useful for Warlocks that use either the Enlightened Spirit or Soul Eater trees to power up their Spell-Like Abilities in those trees.
 * Empower Spell - Increases spellpower by 75 for 15 SP. Useful for Warlocks that use either the Enlightened Spirit or Soul Eater trees to power up their Spell-Like Abilities in those trees.
 * Heighten Spell - Increases spell point cost and allows you to cast all spells at your highest spell level. So if you cast a level 1 spell like Niac's Cold Ray and you can cast level 5 spells, your spell DC will be 10 + 5(spell level) + (spell focus feats) + (charisma modifier) instead of 10 + 1(spell level) + (spell focus feats) + (charisma modifier). This is helpful for any CC casting or instant-death casting.

Other feats
 * Shield Proficiency, Shield Mastery, Improved Shield Mastery
 * Spell Focus: Necromancy
 * Greater Spell Focus: Necromancy
 * Spell Focus: Enchantment
 * Greater Spell Focus: Enchantment
 * Spell Penetration - Gives you a bonus against enemies with Spell Resistance.
 * Greater Spell Penetration - More of above (rarely kept after level 26).
 * Past Life: Arcane Initiate, Past Life: Arcane Prodigy
 * Toughness or Past Life: Berserker's Fury - More hit points.
 * Extend Spell
 * Enlarge Spell - Works on Soul Eater's Consume, Stricken, and Steal Life Force; very useful if you are taking these enhancements.
 * Eschew Materials for convenience in inventory management only. Often preferable to simply buy spell components.

(characters get epic feats at levels 21,24, 27, and 30).
 * Epic Eldritch Blast - Max +7d6 Eldritch Blast damage
 * Ruin - An epic damage spell (500 points of damage).
 * Greater Ruin - requires Ruin (1K damage; also grants 140 spell points)
 * Epic Toughness - 50 hit points (see above in toughness for other requirements).
 * Hellball - a 10th level spell
 * Epic Damage Reduction - +10 PRR
 * Epic Spell Focus
 * Epic Spell Penetration
 * Arcane Insight - +110 spell points; +6 to spell DCs & spell penetration for 30 seconds
 * Wellspring of Power - +110 spell points; +150 universal spell power & +20% spell critical for 30 seconds
 * Embolden Spell - +140 spell points; Metamagic: +2 to DC of spells for +10 spell point cost
 * Intensify Spell - +140 spell points; Metamagic: +75 spellpower for +15 spell point cost (stacks with Empower/Maximize)
 * You can also take heroic [normal] feats if you prefer them

Epic Destiny Feats (can be taken at levels 26, 28, and 29)
 * Epic Pact Dice - Max +6d4 Eldritch Blast damage
 * Epic Spell Power (Force, Light, or Pact damage) - +20 Spell Power
 * Arcane Pulse - DoT, 3d6+6 Force damage every 2 seconds for 16 seconds; stacks up to 5 times.
 * Deific Warding - +10 MRR & PRR, plus up to 10 stacks of +2 MRR/PRR upon taking damage
 * Arcane Warrior - especially if you plan on using your aura while meleeing/ranging

Legendary Feats
 * Scion of the Plane of Earth - +4 Conjuration DCs/+2 other DCs; +20 PRR; +10 Acid/+30 Universal Spellpower; +2d20 acid damage to weapons (scales with spellpower). Especially good for Great Old One pacts & aura/weapon users.
 * Scion of the Plane of Air - +4 Evocation DCs/+2 other DCs; +4% Dodge & Dodge Cap; +10 Electric/+30 Universal Spellpower; +2d20 electric damage to weapons (scales with spellpower). Evocation affects Eldritch Blasts & Tentacles.
 * Scion of the Plane of Fire - +25% Spell Criticals; +10 PRR & MRR; +10 Fire/+30 Universal Spellpower; +2d20 fire damage to weapons (scales with spellpower). Spell crits affect Eldritch Blasts & Bursts, as well as SLAs such as Consume, Stricken, & Steal Life Force.
 * Scion of the Plane of Water - +200 spell points; +20 MRR; +2d20 cold damage to weapons (scales with spellpower). Possibly the least useful of the elemental Planes, though MRR is nice.
 * Scion of the Feywild - +4 Enchantment DCs/+2 other DCs; +10 Sonic/+30 Universal Spellpower; +2d20 sonic damage to weapons (scales with spellpower). Best for Fey pacts, but even they could probably do better.
 * Scion of Celestia - +20 Positive, Light & Alignment Spellpower; +20 Universal Spellpower; +30% crit damage for Positive, Light, & Alignment spells; +150 HP; +4 Will saves. Positive affects Steal Life Force & Cocoon; Light affects bursts (and potentially all attacks, with Enlightened Spirit's Spiritual Retribution); Alignment affects Consume & Stricken, as well as your Eldritch Blasts & bursts with Tainted Scholar's Utterdark Blast.
 * Scion of Elysium - various bonuses to summoned creatures. Especially useful combined with Enlightened Spirit's boosts to summoned creatures.
 * Scion of Arborea - +20 Melee/Ranged Power; +20 Force/+20 Universal Spell Power; +2 weapon Enhancement bonus; +4 Fortitude saves. Good for aura/weapon users as it affects all aspects, particularly if you are using the base Eldritch Blast or Tainted Scholar's Piercing Blast.
 * Scion of Limbo - +2 saves; various random effects. Most effects will have at least some usefulness, either offensively or defensively.

Skills
Many skills can be useful to a Warlock, under the right circumstances. Plan ahead, before you make the character, as far as which skills you'd like to be able to use.
 * Spellcraft increases the damage of the eldritch blast and spells. Maximize it. Increases spellpower by one point per point of spellcraft on most spells.
 * Concentration is highly useful. When you take damage while casting, you roll a Concentration check. If you succeed, the spell is cast. Failure means you used the spell points but the spell did not come into effect. The metamagic feat Quicken Spell can be used to supplement a poor concentration skill at the cost of extra spell points.
 * Use Magic Device allows the warlock to use scrolls and wands made for Divine casters such as Paladins and Clerics. This is almost must-have for fleshy races in order to heal via Divine wands and scrolls.
 * Heal is useful once a warlock reaches 20+ levels and manage to unlock/twist Cocoon. Also good for Soul Eater's Steal Life Force.
 * Tumble is good to spend 1 point on as it will allow you to tumble, which can improve your saves.
 * Perform lets you add charisma and any perform bonus to sonic spellpower, which improves Fey Pact damage.

Situationally useful skills (depends on playstyle):
 * Diplomacy is highly useful. It can allow you to convince enemies to leave you alone. If the party runs into a large group of enemies and one or more of them targets your warlock, you can activate the Diplomacy skill to convince them that some other member of the party is a bigger threat, and they will leave you alone.
 * Balance allows a character to get up faster after he's been knocked down in combat. Since preventing the knockdown requires either high Strength, high Dexterity, or the divine spell Freedom of Movement, investing in this skill can help you to stand back up sooner after some creature does knock you down. (Less useful if you plan on taking Enlightened Spirit's Celestial Spirit stance.)
 * Bluff allows your character to convince certain Non Player Characters to do something for you, or to give you some information. It is rarely useful, but when it is useful, it can sometimes save significant amounts of time. With a Warlock's high Charisma, a few skill points at most is usually sufficient.
 * Haggle will allow you to purchase supplies at slightly lower prices and will improve the price you get for items you sell to vendors.
 * Spot allows you to see enemies who are hiding before they are on top of you and attacking. Some creatures are easier to see than others, but even a few points in spot can make a difference.
 * Jump will allow you to bypass enemies and avoid traps. Note that increasing jump past 40 makes no difference and that 9th level warlock can get to 30 with a the Jump spell (various items and buffs can easily cover the rest). Investing points in Jump can be nice early, but often wasted by mid-levels.

Enhancements
Warlock have access to 4 class-specific trees Soul Eater enhancements, Tainted Scholar enhancements, Enlightened Spirit enhancements and Acolyte of the Skin enhancements.


 * The Soul Eater tree is debuff-oriented tree with cone-shaped area of effect damage options. Use Consume and Stricken to severely weaken enemies. This tree is also used by warlocks wishing to delve into necromancy, as they gain a spell-like ability that mimics the finger of death spell as well as a powerful instant-kill ability in their capstone.


 * The Tainted Scholar is a crowd-control oriented tree with ranged area of effect damage options. Use Eldritch Blast Shape: Chain to hit multiple enemies at once across surprising distances and gain increased potential to deal increased damage with your eldritch blast. The core abilities of the tree give the warlock several new spells, as well.  Most enchantment-based warlocks use this as their primary tree, sowing mass confusion among the enemy ranks.


 * The Enlightened Spirit is an in-your-face damage tree while also being defense-oriented. Use the two point blank area of effect abilities to bomb enemies in melee range and add light damage to your eldritch blasts. This tree is also very useful for warlocks that would rather focus on melee damage, allowing them to turn their eldritch blast into an aura that fires off every few seconds, freeing up the warlock to swing their weapons. Note, this is explicitly mutually exclusive from Acolyte of the Skin, picking one blocks access to the other.


 * The Acolyte of the Skin, which must be chosen at character creation and explicitly blocks access to Enlightened Spirit, is a tree (and archetype) less focused on spell use and more focused on a broad spread of permanent passive defenses, and a stronger focus on and enhancements to the Eldritch Blast. It is also hard-locked to having Fire as its pact damage, can gain the ability to double Pact damage against enemies in a Fear state (as well as multiple abilities/SLAs that can inflict Fear on enemies alongside damage calculated off of Blast stats), and a temporary transformation into a strong Demon melee fighter whose damage is also based on Blast stats. This tree is much more focused on using the Eldritch Blast as your primary damage source, and not spells, than other trees.

Warlocks have access to fairly strong basic attack (Eldritch Blast) and they don't have to rely on cheap SLAs for damage. In fact, in some cases, using the SLAs interrupts the eldritch blast attack sequence and can result in damage loss. Many SLAs are still worth it; particularly for warlocks using the aura shape.

The Warlock's UMD
With the Deceive Item passive (the strongest raw UMD increase passive skill of any class at +10) and a Warlock's naturally very high Charisma, a Warlock is capable of achieving a no-fail UMD score for every wand and scroll in the game with the lowest number of points spent on training the skill. Given the very broad variety of wands, scrolls and potions this grants access to it can be a bit daunting to pick out which ones to use and remember where to find them, but the following general principles can be a good guide:
 * Scrolls/wands of damage-dealing spells won't really be strong enough. Even with Wand and Scroll Mastery from Tainted Scholar enhancements maxed out, the scrolls and wands you have permanent access to from shops won't be able to keep up with your Eldritch Blast and various damage-dealing spells you'll be able to get access to as you get into the Epic levels, so don't bother with them
 * Scrolls/wands/potions of defensive buffs unaffected by Spell Power or the wand/scroll mastery still typically don't have very long durations, which can end up quite clumsy to use in missions
 * In most cases the best UMD items/potions for a Warlock are brief or instant tactical/logistical effects intended to upgrade base stats like Strength to get past puzzles/locks in missions, status curatives or teleports.

With the above stated, the following is an effective baseline set as well as convenient one-stop-shop locations to regularly acquire them (and accordingly you don't need to bother using spell slots on them):
 * Scroll of Raise Dead, Guild Divine scroll vendor House Kundarak, as an emergency backup resurrection ability for allies.
 * Scroll of Tenser's Transformation, Object Desire in House Phiarlan, an Alchemical boost to Dexterity and Strength to deal with puzzles/locks and this stacks with the typical Enhancement bonus found on equipment or the common +4 potions like Potion of Bull's Strength.
 * Potion of Water Breathing, Liquid Charm in House Kundarak, to allow for easy unlimited underwater travel.
 * Potion of Lesser Restoration/Scroll of Restoration, Guild potion vendor House Kundarak for Lesser, Guild Divine scroll vendor House Kundarak, to deal with stat-reduction and various other debuffs.
 * Potion of Poison Neutralization, Guild potion vendor House Kundarak, to clear poison effects before they hit you with a stat debuff
 * Potion of Disease Removal, Guild potion vendor House Kundarak, also to clear diseases before they debuff you.
 * Potion of Curse Removal, Guild potion vendor House Kundarak, similar to the above two.
 * Potion of Blindness Removal, Guild potion vendor House Kundarak, similar to the above.
 * Scroll of Heal, Guild Divine scroll vendor House Kundarak. Good for a decent heal burst to yourself or an ally in a pinch at the lower levels.
 * Potion of Heroism, Guild potion vendor House Kundarak, primarily for the +2 boost to Skill Checks which can be useful for dungeon puzzles/locks
 * Potion of Rage, Guild potion vendor House Kundarak, gives a Morale boost to Strength which stacks with Tenser's Transformation, useful for Strength puzzles
 * Scroll of Teleport, Guild Arcane scroll vendor House Kundarak, allows very easy mobility between the various city locations.

The Warlock's Skill Bars
Despite only gaining 2 "standard" spell slots per each of 6 spell levels, adding on the free spells from most of the Pacts, Tainted Scholar enhancements Core skills, numerous SLAs and buffs spread throughout the trees, abilities/buffs accessible via Feats and the vast number of abilities accessible via UMD it is quite easy for Epic level Warlocks to have upwards of 50 abilities available for use at all times, a number definitely higher than average among classes. Organizing this many abilities for efficient use can be a bit of a trick, but the following suggestions on how to organize each 10-slot skill bar may help:
 * Have one Primary bar, this being the one you have on by default and accessible via hotkeys. These should be abilities you use more often than anything else, such as key burst attack spells/SLAs, defensive buffs that frequently need to be refreshed (e.g. Stoneskin or Shining Through), at least one cheap & short cooldown defensive buff to be able to easily recharge Feigned Health (the Displacement SLA from Enlightened Spirit enhancements is an excellent example), one good self heal ability/consumable and your Main Hand weapon for quick re-equip after use of a scroll or wand
 * Have one Moderate-Use bar, for common use abilities that you don't necessarily need to activate in a flash and could potentially activate by mouse. Good choices are your Blast Forms, your Pact (if it is a type that some enemies may get healed by so you must turn it off), status curatives like Remove Curse/Poison/Disease potions and temporary puzzle related buffs like a scroll of Tenser's Transformation
 * Have one Defense bar, for your mid-duration defensive and logistical buffs like Shield/Nightshield, Resist Energies, Death Ward, Jump, Expeditious Retreat and the like
 * Have one Long Buff bar, for the extensive-duration buffs to monitor their status such as Metamagics, the Spiritual Retribution Imbue (does not persist through a logout), the Celestial Spirit major form (does not persist through a logout or death) and the like

Feel free to tailor your bars as you see fit, based on what works best for your gameplay.

General considerations
The consensus opinion on starting Charisma seems to be that a starting score of 16 to 18 is necessary. Starting with a Charisma score of 18 (or 20 for Drow) maximizes a Warlock's starting save DCs, grants a few bonus spell points and grants a stronger health shield via Feigned Health in the Tainted Scholar enhancements tree. The spell point advantage is minimal, but the higher save DC is very important and the stronger health shield is quite crucial for survivability. Having a higher DC for all of a warlocks offensive spells reduces the chance that enemies will succeed at full or partial saves, making the Warlock more effective overall.

Another school of thought on the subject of having a high Charisma says that in the point buy system, a score of 17 or 18 uses too many resources to be worth the benefit. Proponents of this line of thought believe that spreading stat points around more will make a more effective character overall at the cost of having a lower spell save DC.

Some warlocks ignore (dump) Charisma, accept the low DCs of their spells and Eldritch Blast, and focus on other abilities, for example Constitution or Intelligence.

Conclusion
As a warlock, you will know a very small number of spells, choose carefully. Pact choice and enhancements can expand your repertoire.

Arcane spells fall under one of the categories:


 * 1) Offensive damage spells like Evard's Black Tentacles.
 * 2) Buffs (spells that aid yourself and your allies) such as Jump, Haste, Stoneskin or Shield.
 * 3) Debuffs (spells that hinder enemies) such a Ray of Enfeeblement, Bestow Curse or even Break Enchantment (can be used to remove curses/magic effects from your party or buffs from your enemies).
 * 4) Crowd control spells such as Web or Mass Hold, this type of spell limits the number of attacking enemies or at least hinders their approach.
 * 5) Insta-kill spells like Power Word: Kill or Trap the Soul
 * 6) Utility spells like Dimension Door or Teleport

If built carefully the damage of a Warlock's Eldritch Blast can get VERY high. This combined with the fact that a notable chunk of its damage output completely ignores nearly all known defenses and it can be fired about 1.5 times as fast as spamming damage spells or SLAs, a Warlock with a high damage Eldritch Blast can practically ignore damage-inflicting attack spells, and given the blast's effect on groups while in Cone form their need for crowd control spells is also limited given how quickly they can simply kill masses of enemies while constantly moving backward to keep out of attack range of melee enemies. For some builds this is so prevalent that the only way for most of a Warlock's SLAs and damage spells to keep up on later-level Warlocks is to have multiple damage-increasing Metamagic feats active simultaneously. This in turn can let a Warlock focus all of their spell selections on tactical utility such as defenses and mobility.

The Enlarge Spell Metamagic is a very key counter-consideration to this, however. While the Eldritch Blast can easily out-damage a number of the Warlock's SLAs like Consume or Steal Life Force, Enlarge Spell makes these SLAs rather notably out-range the Eldritch Blast. This can give you some highly useful long-range sniping ability on enemies to add to your arsenal.

Sample build
Race: Human

Ability Scores

 * Str: 8 (0 build points)You won't be winning arm-wrestling contests, but still make sure to have some sort of strength item so you will be able to continue casting after a spell-caster hits you with a Ray of Enfeeblement.This may be too low  and may have to leave loot behind because you are too weak to carry it.
 * Dex: 8 (0 build points) Luckily DDO won't penalize (or even show) you for tripping over your own feet. Your AC doesn't matter at all after somewhere after level 5.
 * Con: 16 (10 build points) You will have enough hit points so that most creatures won't be able to kill you in one hit.
 * Int: 10 (2 build points) You need enough intelligence to maximize spellcraft and use magic device. Everything else can wait for a tome.
 * Wis: 8 (0 build points) Make sure to have some sort of wisdom item for your Will save.
 * Cha: 18 (16 build points) You will be suave, debonaire, and confident. You will have as many spell points as it is possible to have at the start of the game, and your save DCs will be as high as they can be.

Skills

 * Spellcraft increases your Spell Power, making your spells deal more damage.
 * Use Magic Device - Use Magic Device will allow you to use magic items built for other races or alignments. You can use arcane scrolls and wands without this skill, but it comes in handy for self-healing and certain items later in the game.
 * Perform - For Warlocks with the Fey Pact only to increase eldritch blast pact damage.
 * Concentration - You need a high Concentration to cast spells or scrolls while under fire.

Feats

 * At Level 1, Spell Focus: Evocation and Human bonus feat Greater Spell Focus: Evocation. These will make it harder for enemies to save against your pact damage
 * At Level 3, Mental Toughness to increase the critical chance of your eldritch blast.
 * At Level 6, Quicken to cast spells faster and without interruption
 * At Level 9, Improved Mental Toughness to increase the critical chance of your eldritch blast.
 * At Level 12, 15, 18 Take Toughness three times for more hit points. If you want to use the SLAs in Soul Eater or Enlightened Spirit Trees, take Maximize Spell and Empower Spell. Take Heighten, Spell Focus Necromancy/Enchantment and Spell Penetration feats if you want to cast crowd control or instant-death spells. This sample build focuses strictly on empowering the eldritch blasts via the Tainted Scholar (and Enlightened Spirit) lines. So it's not necessary to include Maximize and Empower for certain Warlock builds because they DON'T affect the regular Eldritch Blasts.

Alternatively, you could invest in your defenses, using stuff like Force of Personality or even Resilience.

Enhancements

 * Start with the Tainted Scholar line. Take Eldritch Blast Shape: Chain and Increase the Eldritch Blast Pact damage with Strong Pact. Take Feigned Health and Eldritch Focus. Also Take Tainted Lore for increased Critical Damage. Take 2 increases to Charisma.
 * Slowly build up the Enlightened Spirit Line. Take Resilience of Body and Resilience of Soul. You need to work your way up to Spiritual Retribution Tier 4 for increased Eldritch Blast damage so take the prerequisites Spiritual Defense, Spiritual Bastion, and Spiritual Ward. Also take Power of Enlightenment. Take 2 increases to Charisma.

Spells
Pick a few of these, and if you find that one is less useful than you thought it might be, go back to the trainer and pay a small fee to replace the spell with another one. See also full list.

Level 1 spells:
 * Resist Energy is needed if you don't have guild resists and can't afford the +20 potions in the twelve. Eventually (at 11th level or so) take it anyway to give full protection without worrying about ship buffs.
 * Nightshield to nullify enemy magic missiles and provide a boost to saves.
 * Jump at 9th level it will nearly max out you jump score on its own (30 points out of a maximum 40), and by that point you aren't using many first level spells for damage
 * Master's Touch will surprise those unfamiliar with DDO. A greataxe is still an effective weapon in the hands of a warlock who dumped strength, as long as he has cast Master's Touch. Using the axe can save SP on longer adventures, and where monsters resist your favorite spells.

Level 2 spells:
 * Invisibility If you don't want to buy sometimes expensive invisibility potions or wands from the auction house
 * Protection from Energy Useful until you have access to a more powerful form of the spell or are multiclassing with fewer levels of Warlock (Use 10/10 class split to get past life feats while rolling through content with Warlock)
 * Blur For defense
 * Web A handy crowd control spell for Warlocks. Warning: fire spells will often burn the web away.

Level 3 spells:
 * Dimension Door to return to quest entrances faster, very useful for zerging.
 * Displacement for defense
 * Haste for fast movement
 * Stoneskin for defense

Level 4 spells:
 * Teleport for fast travel
 * Evard's Black Tentacles area of effect slow and damage

Level 5 spells:
 * Greater Teleport for fast travel
 * Finger of Death instant kill or good single-target damage.
 * Protection from Elements, Mass to protect a group of allies.

Level 6 spells:
 * Wail of the Banshee for area of effect instant death.
 * Hold Monster, Mass for area of effect crowd control.