h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

as far as I know, chess players are very orderly, mathematically oriented people and you can easily annoy them by very precisely NOT placing your pieces in the center of a field, but always offset to one or another side. I think Kasparov often used this technique to his advantage. (I'm not a chess player anyway, just heard of this once)

Another one is when playing with clocks, petulantly press your opponent's clock for them if they take more than half a second to press it.

Or if your opponent spends ages thinking before making a move you were expecting, sneer and toss your head nonchalantly before moving. Note that this can fall flat on its face if you missed an obvious checkmate on your opponent's next move.

on the clock thing - sure try it, if you want to be disqualified from the game or even the match