I avoid clustering with my team mates. Whenever there is 2-3 of us near the same spot i always get the urge to move the hell away.
I sometimes have the urge to avoid obvious spots for snipers. Instead of going into the best ever spot that gives me a perfect view, and also a perfect chance to get shot. I almost always go into a different spot that isn't perfect for sniping but people never look at.
I unknowingly position myself so that there isn't any parts of me poking through a wall or most of me is hidden.
I avoid recently dead bodies like the black plague. Even in other games. Damn martyrdom.