I normally play McMourning, but yesterday I had my first go with Kirai.
It will take some time to get her really going I guess. The things to watch out for the most:
1/ Keep her close enough to the battle ( within 8 inches )
2/ Summon Ikiryo next to an enemy that has already activated this turn, otherwise Ikiryo gets slaughtered and Kirai stays behind with 4 unhealed wounds!
3/ The constant struggle to heal Kirai: it's not that easy... especially since you need to get "In the spirit world" off.
I think sacrificing Ikiryo yourself makes a big difference in this.
It was fun, especially the big movement-tricks you can do with her. But it's so easy to forget about all the small things...
I've mostly read the tactic already posted, but any suggestions are always welcome!