SMG and laser sight and just hip fire your way to glory.
But really, it's the only thing that really works right now. Assault rifles don't feel that good at all. The maps are so small that there are hardly any advantages to an AR. Just do what everyone else does and roll with an SMG, laser sight, silencer, 2 shock charges and 2 bouncing betties.
Think i might have done my thumb sticks in too. You can't stop at all on this game otherwise people spawn behind you. So the best thing to do, is keep running about all over the map mindlessly. Stay of out any long points where you can get shot with an AR or Sniper and you will be lol'ing to victory. It's a terrible way to play the game, but that's how it is.