I recently wrote to I.M. John Donaldson asking for some ideas for OTB players regarding travel tips, lodging, what to bring (and not bring) food, exercise and other tips that players can use to get the most from their tournament experience. I had the honor of working with John on some articles in Northwest Chess and played against him in a few simultaneous exhibitions in the early 90s (I never made it past move 40!) His email response is below. John has played in a great many tournaments in Europe and the US over the last 50 years and seemed interested in writing a more expanded article on the subject. Hope this might be of interest to some of you.
Preparation away from the board is subject not well discussed in chess literature, perhaps in part because it depends so much on the individual. There are some articles, for example.
https://en.chessbase.com/post/che-and-nutrition-how-to-feed-a-che-grandmaster
Applying Logic in Chess by Erik Kislik touches on some of the issues you raise.
I would aim for nutritious meals with an emphasis on whole grains (slower burning carbs) , aiming to eat two hours before rounds, but this is not always possible. Likewise, getting a good night's sleep is important, but again sometimes hard to get in.
Going for a walk between rounds, getting some fresh air and taking one's mind off chess, is a good idea when possible.
Make sure to stay hydrated during the game with a beverage or water - something not high in sugar. Experiment and see what works for you.
John
HI mchill,
The best piece of advice was ' Experiment and see what works for you.'
I always like to be away from everyone for 10 minutes before a game to put myself
in the zone. I never hawked around the score board seeing the results. I knew that
if I kept winning then the scoreboard would take care of itself.
I was into chewing gum at the board. It helped (or I believe it helped which is important.)
If you find you have played a good game and everything went well. Remember
what you did before and during the game. That is your routine.