Don't show up at a spot with six buddies and dominate. Pull up by yourself. Paddle out by yourself. And don't hog all the waves. It's as easy as that.
If you are car-pooling (good for you!), spread out.
There are few things as annoying as enjoying a nice session and having it instantly crowd-ified by a single group.
Be cool. Be mellow. And enjoy.
Lars and the 42 Crew