Kick the ball out of play if you see one of your own or opponents players is injured.
Do not argue with the referee, he is doing his job.
Do not argue with your manager he is also doing his job.
Do not use bad language.
Try to stay on your feet when tackled, no-one likes a diver.
Support your team mates, even when they are not playing well or struggling.
Shake hands or how about three cheers for the opposition after a game, win lose or draw.
Deliberate handball? Do not dare !
Always be a good loser