Don’t speak for the teacher
Example: Do not come up to me in your child’s presence and say “Johnny would have learned this faster if he had listened to the practice CD, wouldn’t he have, Ms. Dorla?”
Why not: One of the things you pay me for is the expertise in knowing how to balance correction and encouragement. You also pay me to diagnose problems and to provide remedial action. Johnny may be having trouble learning the patterns at the piano because he is struggling to recognize patterns.
What to do instead: In this example, either let me discover that the student had difficulty finding the pattern on the piano, or simply tell me “Johnny really had a hard time learning the piece. He was in tears twice this week.” Sometimes it is better to say something privately, and other times it is reassuring to the student to hear their parent “back them up.” Use your parental judgment as to which approach to take.