Artificer tactics

Ranged tactics
You are bringing solid crossbow DPS into quests. Try stay in close range in order to benefit from increased damage via Point Blank Shot. Improve your burst DPS with Endless Fusillade and/or runearm blasts. When partying with melee characters, try not to kite monsters away from their melee range, they hate that. In fact, as would be your combat role as any ranged character, wait for the tanks to engage, Intimidate, and pull aggro first before opening up with the crossbow and spells. Additionally, using the Precise Shot Archer's Focus stance requires you to stand still to increase your damage, up to 25%. This means you need to figure out a good place to stand when all the mobs come out, to maximize your ability to turn the bad guys into your personal pincushions. Stay back with the casters and other ranged characters; rely on your runearm to deal with the trash that gets by the tanks closer to you. (Think of yourself as carrying an assault rifle or sniper rifle and a shotgun, and deal with your opponents accordingly.) As always, target the enemy spellcasters first. Even though they tend to go down quickly, they are often in places melee characters can't get to, and are much more dangerous to the party. Using your TAB key to scroll through and select available targets, along with your Precise Shot/Improved Precise Shot, helps immensely, especially as you will be shooting past and through melee characters and trash mobs to hit the casters.

Dogs
Your iron doggies are a useful asset throughout your journey to level 25. However, note that dogs are stupid and in some quests (especially end game/epics) they are often a liability (e.g. running off causing unwanted aggro). Please check with your party before calling your dog in a quest you are not familiar with.

End game raid tactics
As suggested by Shade in a forum thread, artificers are the ultimate scroll healers, able to cast heal scrolls at caster level 15 with +75 % effectiveness, for a total of 262 HP (before Healing Amplification).