Dr. Oz, on today's episode, said that a breakfast of eggs, wheat bread, and a cup of coffee will help you focus. He also suggested 100mg of ginseng twice a day and noise-canceling headphones.

I'd like to add that I know for a fact that 20 minutes of good huffing and puffing aerobic exercise on the day of a tournament will help, too. It provides blood flow to the area of the brain where focus and creative thinking are necessary. Meditation also greatly increases your ability to focus. As little as 20 minutes a day, 3-4 times a week provides many benefits (more than just improved focus).

You mean I should get off my ass and go back to the gym?

On tournament days, yes. Your mind will be clearer after a good huff-puff workout. I can find the article and post it here.