Many players despise campers, or players who stay in one undisclosed spot and attack passersby, but you should recognize that it is nothing more than another style of play. Thus, you should keep the following tips in mind:
Don't camp in the obvious camping locations. Camping spots that are created specifically for the purpose of camping are the worst. These would include sniper balconies, the top of huge towers, other "secluded" locations that stand out in the open. Every experienced player knows where these locations are, and you're essentially a sitting duck by standing there. As a rough standard, any camping spot that has a weapon spawn [e.g. a sniper rifle] is probably a well-known camping spot.
Don't stay in one spot for too long. Even beginners will pick up on your game after two or three kills, and will develop a strategy to sneak up and take you out. Find a spot, make two or three kills, and escape to another spot. Don't camp too often. You might incorporate camping into your gameplay from time to time, but you shouldn't base your entire style on it. You will become too predictable of a player, and your opponents will quickly learn how to defeat you.