I remember that when I played for first time in a live concert, mi proffesor, Eduardo, took to me about some things, I remember his words... "When you going to play on a live concert, you need concider some recomendations. First, the week before the concert, the study of the piece must be focused on finding the best possible sound, then, in theory, the tecnical troubles were resolved before. Second, the day before the concert, you need repose too much, you need sleep early and eat light foods, this time is for think in the pieces, but not too, you only need this time for relflection. Third, the day of the concert, you need concider in all the cases, do a inspection of the concert venue, check their acoustic characteristics and imagine your disposition on this place, is highly recomended too, eat light foods and drink water, just before play, will be fine eat a chocolat or some similar thing. Now, when you're playing, you need have present that if you start a piece, you can not stop, if you have some trouble or something, never can stop of play, you need improvise or invent some way to scape of the situation, and resume the piece, only if the error was impossible to solve, you can stop, give a public apologies and begin again."
I always remind his words, hereby I wanted to share with you these suggestions and I hope some of them serve them, as I have served me for years.
Many greetings!