Equip bomb kit and run away from mobs. :) Circling back in with a dodge with a bomb trait when you dodge. I up as much condition dmg I can and make sure crits and hits add burning and bleeding dmg. I increase bomb radius as well with explosive traits. I up my tool traits so I can lay more dmg as well. Its effective AoE dmg and can wipe massive ammounts of melee mobs. Doesn't work so hot for ranged attackers. I switch back to ranged for that.
I am new to reading and posting builds. This build is strictly PvE and hasn't been tested for anything else. Its funny to watch 15 or more trying to attack you while you run laying bombs at their feet. Works well for some dungeon situations. Then again, I am new to dungeons as well, and die to often to give much advice there.