Hiding your ultimate goal from the opponent, find a roundabout way to win instead of directly pursuing the target. You can walk into the arena, but don’t pick the opponent that you really want to defeat. Likewise, if you’re trying to save money, do go into the store and look around—but don’t let them know what you want or how badly you want it, so that when you see an opportunity to get a special offer, you are able to seize it.
Deceive. Feigning disinterest in something that you have a burning desire for may open an opportunity for a salesman to increase the discount to get your attention.
This one is difficult. If you can suss someone’s real desire, by nonverbal cues or otherwise, you are in a good place to pick up on deception in general.