The most important point to know about preparing for a performance is that it is exactly the same as every day practice! Day by day the student is building general skill as well as deepening their understanding/knowledge of the particular piece they are playing.
Before a performance the practice should have become easy. Do all of the spots many times. Practice slowly, hands separate. Practice with metronome if assigned. Memorize tempo by playing the beginning phrase/part many times. Practice the ending. Go through the same process that has been assigned in previous weeks.
At the lesson before the performance there are no “new” points. This way the piece will be internalized and feel easy without lots of things to remember.
In the few days before the recital teachers and parents can help focus attention on the sound.
For example, “Listen for the the deep and light sounds.” It is good to make the instruction on listening one holistic point rather than several different points of listening to remember. When the child is able to go directly to the sound awareness they will be able to concentrate in the performance environment.
It is not useful to play the piece through at the performance tempo hands together many times. This can actually create anxiety about performing when the student makes a mistake, or the quality goes down.
It is useful to practice the performance aspects of the recital ahead: Bow, get ready, play the beginning, play the ending, bow, walk off stage. This gives the child a sense of the whole performance.
It is also good to let the child focus on their performance piece 2 or 3 days ahead of the recital, without working on the other parts of the practice (technique, new pieces, review, reading.) This will also enable them to spend more time on the piece.
This is a critical time for repeat listening of the performance piece only on low volume. This will make playing the piece very familiar and natural for the child. It gives the student freedom to create the piece as they want it to sound.
On the day before and day of the recital it is good to take care of the basics carefully-enough sleep, good food, good feelings, practice, space to relax, and enough time to get ready and drive without rushing. It takes a whole day to do the best preparation. This is an important ability to foster in the child: preparation- the process of making ready.