One thing that I haven’t seen mentioned yet is that fact that you need to keep moving in this game. Almost all abilities are able to be used while on the go, so instead of standing in one spot and attacking your foe, make sure to keep one finger on a strafe button while fine-tuning your movement with your mouse, and attack at the same time. I usually run circles around my enemy while simultaneously attacking.
You will find that far less attacks will actually hit you.