Green is a squad mate, blue is a team mate, orange is enemy
Drop ammo/medi packs in areas where there is a lot of traffic, you'll pick up a lot of extra points, people will call if they need it, or you can see their health bar above their head, although you get a lot of people that don't bother, so you're dry on ammo, you request some, but it falls on deaf ears. You'll get a defib eventually aswell, allows you to revive dead team mates, little electric shock/skull appears above their body, you get 100 pts for reviving, same as a kill.
I don't talk on it either, i've not found a lot that do have their headsets, but its still fine. Can be annoying be when you get people that are not interested in playing the objective though, you get right up next to an mcom station, heavily guarded, so you wait for squad mates to spawn on you, but when they do, they **** off in the other direction!