Originally Posted by
Eloah
While placement of the faerie is important 9/10 times she can just follow you. And if your spell/AoE can reach the party, so can hers. Placement is really important when you need to be a significant distance away to avoid some mechanics, or to just keep yourself out of harms way: Phantom Train, A9/S, A12/S, T5, and I'm sure there are more. But, usually the battle field is a circle, and the distance you'd normally stay at to keep yourself safe is good for her as well, since most of the time the boss/mob is tanked dead center.
That being said, the really important thing is controlling yiur faerie by having her on Obey, and manually entering her skills.