[Amsiroth]

Keeping your distance seems to be the best thing at points. Nothing like a Kamikaze mage using every aoe he has to burn you down quick.

Use your spell interupts: death coil, fear, seduce, spell lock, felguard intercept.

Other than that, just practice.

Of course, none of this defends you from Sniper Mages who land while you are farming, then throw a trinket'd POM Pyro your way for 8k when you only have 7250 health...