PVP in this game (control at least) is entirely about knowing what battles to pick and knowing the maps. If you have two control points under lock down and they keep rushing you to die, then don't push for that third and -blam!- it all up. Know your maps and change your load outs as required. I change up my weapons almost every match, and play a different subclass based on what map we are on. Firebase I always run as a stryker with armentarium. Why? Because I can tag a lightning grenade into each corridor by B to weaken/kill the enemy to try and force them to come through up top. I run defender on Twilight gap with st 14 to create a choke point from C-A. It's really all practice practice practice and knowing when to change your play style.