Even if you just meet some people ingame and you know they know what they're doing, it helps. I ended up behind an enemy base as a medic, and noticed my friend (just played a few rounds with him in my squad, communicating etc, then quit, and joined another game he was in but different squads) was there too. We end up running around without any contact, and stealing the defenders' Apache.
Boy, imagine Attackers getting an attack helicopter, and tanks, vs the defender having only a light tank and two exposed crates.
I went 43/10 (13/10 before the heli, I was gunner) that round... It was amazing. Got my last two vehicle unlocks (TWO FULL BARS!) from that, and roughly 30-40 pins. Then we got shot down by a blackhawk when we finally blew the crates (we needed to repair so we were distracted).
That was crazy, but I followed him explicitly because I knew he was decent. He barely even shot rockets, and he mostly just circled and let me keep firing. (we had no communication either)
I've been rolled several times by heli's on the opposing team, so this was a real refreshing experience.
Oh, and Spec 3s stack with people in vehicles, so try to coordinate with the other person if you find yourself in vehicles often. (Most tank gunners like Optics, I personally love Fast Reload, so imagine that combo)
Now I'm jonesing to play again today
