Overview
Include number of players, summary of play. If there's a background story or plot exposition, this is a good place for that.

Setup
How should the board/playing area be set up to start?
What equipment (cards, tokens, etc.) should be given to each player?

Turns
How do you determine which player goes first? Do players take turns sequentially, or play simultaneously?
What happens during a turn?
Which player goes next? Is it round-robin, or do players win the right to go next somehow. Is there some other mechanism for determining the next player?

Winning
Under what circumstances does play end?
How is the winner determined?

Variations
Are there other suggessted ways to play?
Changes to adjust for different numbers of players?