When you exchange pieces, always put one of your opponent's pawn or piece on your lap or hidden in your other hand. If your opponent likes to compare the pieces that have been exchanged, he will think he is winning and ease up a bit. If you are a piece up, roll the extra piece in your hands or toss it up in the air a few times. Find an extra queen from another board and have it nearby, indicating you may soon queen a pawn. For the musically inclined, humming is a favorite nuisance.
Aggressive players can go into a full song accompanied by the gestures of a conductor.
Bringing a radio along and occasionally turning it on during critical times of the game works. If your opponent is a sports fan, tune in to some important sports event. When smoking is allowed, it is best to get the foulest, blackest cigars or pipes. A lot of smoke towards your opponent not only obscures the position of the board, but causes your opponent to choke and become blind from the smoke in his eyes. A method popular among grandmasters for annoying an opponent is to stare directly and deliberately at your opponent.