Don't tank more than 2 elite casters. Fear, stun one that's giving you trouble, keep interrupting, use heal pots, drink after each fight.
Edit: Celke: Yeah, I told you the gear makes or breaks the spec. If you have it, this spec pwns. If you don't the damage is weak, and especially if you don't have Arkryon's Mirror, you're not healing yourself like you should be.