1. Never look at your opponent, especially not at his/her face, try not to look at the body. If you are right handed, place your left palm at a 90 degree angle to your forhead, thus shielding your eyes.
2. Mumble all the variations you are considering, but very silently.
3. The tip of your pen/pencil MUST point toward your opponent's head.
4. Whenever you capture a piece, put it in your pocket, never on the table.
5. Pretend you don't understand a word of English, especially if approached by an arbiter.
Generations of Welsh players have kissed the ceremonial sheep before tournaments without realising that it is actually just a superstition not a requirement. I know. I've checked the WCF rulebook - it's not in there. I could hardly believe it either.
I have three minor foibles during sanctioned tournament games that could be described as superstitious:
Do any of the other players out there have any small superstitious rituals that they use to bring them luck in their games?