As music teachers, we are often asked the question about how to get kids to practice. Here are some ideas that have helped other parents:
Remember, learning music is always a partnership. For children it's a partnership between student, teacher, and parents. If practice isn't where it should be, leverage the partnership and start a conversation between all three parties. Decide on a strategy that the student is invested in, the parent can support, and the teacher can check in on. Set things up to give the strategy its best shot, and if it's not working after a couple of weeks, try a new strategy!