Well, increase firearms, get better weapons, mod those weapons. I would suggest high risk targets, as they have a chance to either drop 2 set pieces or a set peice and a 204 gun. DZ is also a good loot place now, just avoid players and keep some distance between you and your teammates. When extracting hid behind cover until the Thierry second mark left before the helicopter leaves, that way your loot is almost definitely safe.

Increase your firearms skill and use guns with higher dps, then attach mods to increase the dps of that gun.