When you look for a piano teacher, also see what activities they have the student doing in their studio. Do they have recitals? Are they involved with their local Music Teachers Association? Do they do the Royal Conservatory Music Development Program assessments for their students? All the different events ensure that the teacher is doing their best to give their students regularly scheduled opportunities to perform. Do they get the opportunity to play in front of Adjudicators, other teachers? A teacher who does this ensures that in addition to giving your student a wonderful opportunity to celebrate their achievement, that they are also always learning from others.
Often one to two recitals a year is not enough to get the student over jitters. Does the teacher do performance classes or performance parties to prime the student's ability to play in front of their peers before the big event? This is important to help stop the jitters and get the student used to performing in front of others on a small scale before they do so on a large scale.
Remember, practicing piano at home alone is not enough. Yes, the student may become proficient, but they will play at a MUCH higher level, and be more accomplished if they have a major event such as assessments to study for.