Learn how to use vehicles and your favourite weapons in training servers. Use the "Filter by Server name" box to find training or vehicle servers.
Go to empty servers and explore the maps for a few minutes to know how the map is arranged.
Stay close to other people, this isn't Call of Duty.
If you're using the support class, get some C4 and try predicting where people might be (like in the corner of a building) and use the C4 to blow them up (toss the C4 on the outside of the building so they won't see you). If you're wrong, you can just resupply.
Play on Team Deathmatch servers to do good old killing without vehicles or objectives.