Ooh, I remember going to one of those things once like a year or two ago. I can't claim to be a master strategist, but I can tell you a few useful things I learned from that not-so-pleasant time.
First of all, an obvious one: It's probably a good idea that most of your team stays on constant movement. If you all stick to one place, the other team most likely going to sorround you and leave miracles as your only chance.
It would also help to know the place where you'll play. Do you know something other than just the places being woods and urban? If you know the layouts you probably won't have much of a problem planning your moves, but I've rarely heard of a paintball match were anyone was told of the terrain beforehand (except the one who organized it). Otherwise, be ready to make a quick plan from a few predetermined moves.
Another obvious one: DON'T try pull a Rambo.
It might look cool (and who am I to say it isn't), but going guns blazing is never a good strategy and obviously depends more on luck than anything. (unless there's tall grass, I guess) Also, bring a helmet if you can. It's better to prevent than being sorry later, I say this because I had a bump on my head for a few days after it, and those things often have long range - in other words, lotsa pressure pushing out the balls. They don't kid when saying you need thick clothing. Maybe the bump is because I got hit from a short distance, though. That said, I don't know what kind of guns you'll use, and since the ones we used were pro stuff (dunno how they paid that, since I was just a guest), you might not need that much cover, depends on the equipment, I guess.
I was dragged to go Paintballing once years ago and hated it. Other than advising you not to go at all I'd suggest thick clothing as others have said. Although not too think depending on your climate of course.
Yeah, it's also important to consider how thick your clothing is. Provided the weather is too hot
and you don't like sweating, you might want to take some extra time thinking how to deal with that. Still, use something decently thick. As I said above, you never know if they could hit you from short range. I think I had a bump in my shoulder for a few days after that; it's not the most painful thing that could ever happen to you, but I certainly could have done without it.
There's really no strategy to it unless you like to hide alot and be stealthy. Just have fun with it.
Well, that depends on the opponent, I guess. My team didn't have much of a strategy, and we got royally owned.
Being stealthy wouldn't have hurt much, actually. I can see a few issues with the urban map, though, since tall grass (if there is) helps A LOT.
Anyway, I guess some of this is too basic. But I hope it helps. Hope you have fun, too!
As for strategy i tend to stick to one, maybe two spots in the middle and pick people of. Although i wouldn't suggest this if your playing a respawn game. Anyways at the end of the day just have fun 
