Division 1? Blue ultimate, medkit bonuses and ammo return on headshots, gg. Its really all about a highly accurate rapid fire weapon and constant headshots if you want to dps. The build should just enable as much of that as possible.
Í would advise you to level to cap as soon as possible and dive into multiplayer content or grab those special sets as soon as you can, they really make the game a lot more fun, you can actually develop different playstyles instead of eternal cover hugging. Its pretty deep if you explore the endgame. Don't get burned out from the campaign before trying that is my advice. Farm XP, and go MP. Its not that hard to get nice gear these days either. Couple of intense weeks, probably
I'm not sure how different the early XP farming is from launch days but I just ran around town getting collectibles and doing all those events that pop up. That and the constant enemy spawns get you pretty far and its pretty low intensity, so easy to keep up and not die all the time. Its also fun, imo. Exploration is pretty cool, nice scenery and all
THe missions are pretty hardcore in comparison especially without a half capable ally or two. That is also why you want to cap fast - its the same content, but a bit higher level/dmg and you just get better stuff plus better allies.