Preparedness for a game that usually lasts four-five hours requires good physical condition and also steady nerves.

Chess as a sport requires a lot of mental stamina, and this is what that makes it different from a physical sport. Chess players have a unique ability of taking in a lot of information and remembering relevant bits. So, memory and mental stamina are the key attributes.

Before a game, I avoid having a heavy meal so that I don't feel sleepy at the board. You eat to be healthy, and that generally takes care of everything. Also, you can't be too finicky, since at tournaments you tend to eat at restaurants here and there. But, as long as you're eating sensibly, it's all good.

I attend to my fitness. I go the gym every day and try to maintain my physical fitness; without that, it is tough to take challenges on the chess board.

To be in good moral condition requires at least as much training as to be in good physical condition.

If revenge motivates you, go for it! But the main thing is to set your game in order.