Clothing
Wear nothing but a single black dress sock on your left foot. You'll be sure to win, because your opponents will be too afraid to play you!
Wear something in which you can spend hours in without getting to stuffy or hot...make sure you are comfortable in a tournament! ;)
I tried the sock trick once. As soon as I stepped out of my apartment to go to the tournament hall, I was immediately harrassed by a pack of lusty women. I never got to the chess tournament.
Rookie mistake: You've got to wear the second sock while in transit -- don't take it off until you're actually at the tournament hall.
I've noticed that for most people, the body temperature tends to waver during intensive physical or mental activity, so the temperature in in the hall will suddenly feel a lot colder, or sometimes less. That will explain why a lot of players will wear layers, like a jacket or sweater that they can add to or take off as the need arises.
I don't know what to wear to a chess tournament. Because I have my first tournament in July so please help... Thanks