The art of waving your hands in someone's face in such a way that they beat themself to death trying to block your punches.

There are a few basic rules when trying to psyche someone out. They can be applied to any game of the mind. Poker is good.

The opponent may not know they are playing the game.

This is the most important rule. If this is followed, you are guaranteed victory. As long as they don't know you're psyching them out, you can do what you like to their feeble little mind.

The opponent may not know the rules of the game.

Well, this is fairly obvious. Don't let them know anything which might be an advantage. Such as how to play.

The opponent may not know who has won the game.

As soon as you start lording a psychological victory over someone, it loses all meaning. Let them leave the game thinking that you probably won but not quite sure how or why.