Stay on the move!  Successful players manage to survive longer when they stay on the move, and change positions frequently.  When players move during a game, they are hard to hit.  Move around keep moving until you have your enemy in a position where you think that you can make high percentage shots, and be vigilant towards finding the best angles to shoot from to take your most effective shots at the enemy.  Also, try making yourself small....  When you are hiding behind a bunker, or running across the paintball field, try to make yourself as small as you can, giving your opponents a smaller target to shoot at.  If you are behind a snake bunker, then you must crawl or dive to avoid an enemy elimination.  When behind a short or thin bunker, think about all of your paintball gear, and make sure nothing is sticking out far enough for the enemy to hit it.