To be mentally prepared for the future situation, (what might happen or what will happen) apply the following exercise that takes only 4-5 minutes. It might help you.
At night when you lie down and relax, think of your performance lively as if it is happening at that moment.
Imagine yourself completely calm and cheerful, and with the only motive that you are going to present yourself and your music to a wonderful audience. Imagine that the program has began, you hear the applause, you are being announced, you come to the stage smiling and full of confidence. Think how you are doing the preliminary action before the performance (as described in this booklet) and how you begin to play. You feel comfortable. You see how everything goes on according to the plan and how the audience enjoys in your interpretation.
Imagine yourself also when you make mistakes, but despite them you are calm and you continue playing without panic. You see, for example, that someone is talking in the hall, or that someone is laughing or shouting at you angrily in the moment of playing, but you are calm, you overcome the situation, and continue to play well.
You can imagine any situation in which you can find yourself but it is important to conjure images of a happy outcome.
What do you actually do in this way? You prepare yourself for a future event, ie. how to “come out” of it successfully.
This can also be practiced in the morning when you wake up. So, it means 2-3 times a day until the day of performance when the whole situation becomes clear to you. Many people think about it only on the day when it happens. But it is too late then, because they have not been through the future performance.
Taken from my book