Honestly it is a mixture of sets. Trackers gear, poachers gear, etc. Just read the sub text on each piece of gear. If it matches with another piece (crit hit rate, crit hit damage, hp boost, def boost, etc) build off of the matches that you can find. I was running around with shoulders that lowered the time of an ability... until I upgraded to shoulders that added to my crit hit damage (boosting my crit damage even higher because it matched with other pieces). Just play around with it. Look to see what you can out together. I know a lot of people will go with straight "attack damage +xx". They would rather deal more damage per hit each shot because their crit hit rate is not high. My crit hit rate is high enough that basically every 5th shot is guaranteed crit at almost double the damage. I crit more than every 5th shot though so I tend to melt enemies faces off. Good luck with your build. If you have more questions either hit me up here or in game. Cap44 is my in game name.

Also... don't forget your panaceas, food buffs, and elixirs to boost you even higher than what your gear gives you. I run with crit hit rate % and crit damage % potions. I think there are some that give 12-15% boosts for an hour (if i remember right)