Career
Medic
SMGs and keeping the squad alive.
The Medic career levels from SMGs and medical tools. A good medic keeps a squad in the Control Zone when it should have wiped, and it levels fast because there is always someone to patch. One of the six Careers.
Know the wiki. Now play the game.
AE Gaming runs organised WARDOGS every night with free comms, a planning map and a base builder. Reading is half of it, the other half is a squad.