Physically:
1. Players should always be hydrated, but shouldn't drink too much water.
2. If players know that they are week in their knees they could wear a protective covering.
3. Players should warm up before the game, to reduce risk of injuries.
4. (This is kind og obvious) but players shouldn't play if they already have injuries, minor or not.
Mentally:
1. Before the game, players should be in a good mood, not distracted by events that happened prior to the starting of the game.
2. Players shouldn't worry about losing and focus on the game.
3. Players should be content with their teamates, that is very important.