If you're getting laggy you can always just reduce the graphic settings a notch, if you can cope with not being able to see the paint drying on your brand new cap ships of course. Aside from that I'd suggest closing down all unnecessary background programs and the likes (use the task manager to close down extraneous processes). If you're playing online the best I can suggest is not using other programs that take up bandwidth and, if you're willing to risk it, shutting down your firewall for the game. Also, other people using the internet in the house will sap your bandwidth, especially if they're idiots who click yes for every advert bar in the world.