Ok, yes I understand there is another post with a similar topic.. my method is completely different and doesn't require some odd spot to stand in while attacking. Alright, I only know this works with melee classes but I'm fairly certain its all about how you move around and not just attacking. What I do is stand on one of those floating rocks and shoot one out of the sky, when he comes in melee range I start attacking him but I keep moving, don't stand in one place, zig-zag around and he will just basically follow you but doing no damage.
This of course will take a little practice to get used to.. but its well worth it if you pick an area where you can keep tagging them quick with little down time. Little tip though.. try not to make loops or go in circles.. I've noticed that it usually breaks what I got going on and they will start attacking.