@OP: You didn't specify you were failing on which mechanic... so I'm going to assume you died to green slimes on the ground.

The key to it is not to keep moving. You see, you only move when the green thing spawns at your feet as it will take 2 seconds b4 it "explodes" and affect you. So you just move out of it, stop, wait for another one to spawn, then move out... rinse and repeat.

If you're having issues with adds killing you, then go on a party with a tank (barb/monk), with a healer and 2 dpsers (including you). I did that in hell mode after getting killed by adds endlessly and it was so much easier. My group comprised of witch doc, mage, myself the DH and a monk tank all from pug.

If you're dying due to other issues, then please update the post so we know how to help advice...