The number one tip at this time of year, is to get some anti-mist stuff for your mask. Some use fairy liquid. Or buy one with a pinlock/foggy type double layer. I got one for about 25 quid a few years ago. Worth every penny.
A good site will provide extra paint containers so you can stick another 100 in your pocket. Always handy if you run out halfway through a game.
Most people who are not used to play paintball, seems to think that they have to use the gun like a real rifle and support it in to your body. This is the worst mistake as you expose your body when you do that.
Most important thing is to keep your body hidden as much as you can and be a very small target.
SO only stick your gun out from the cover in angle, so that they can see only your ball loader and some of your head. Then your pretty much invincible :w00t:
Saw much worse brusing on a girl than that (she was at the swimming pool about a week after paintballing and was covered in awful bruises). That coupled with the disclaimer form they make you sign beforehand put me right off it:sick: