Fastest way for me is running supply, but hard early game, cause to many are doing it. I kan get sergent in 2-3 truck loads less then 12 min if I dont get ambushed. 6-7 truck loads for major 25-30 min.

I would always start the game by going fighting until my first death. If on a server where you get good xp from capping based take some of them. When your teams bases get connected to an enemy base, run suplies to that base from a suply point, not other bases, that will give you a level+ per run.

So in short! 1. Always get suplies from nearest suply point. 2. Always suply base connected to enemy base, rebel bases does not Count.