So I humbly offer what I've learnt as an ordinary mortal about helping my kids with their music.
1. They will want to quit - often. Don't give in. There are so many great reasons for persevering with music. Plus you've forked out quite a lot of money so you need to be sure you want to cave in.
2. They might weep in frustration - often. It is not easy learning an instrument. If another person says, 'O, your kids are sooo talented' I might do some physical harm. It is just hard work (for all of us).
3. Get them to listen to the pieces they are learning played by a professional. It helps them know what they're aiming for. It helps me to know what they're aiming for!
4. Your music teacher will generally hope for more practice than you will achieve (if you're an ordinary person). And if they don't they are probably not worth the money you're paying them. You do want lots of motivation and accountability to come from your lessons.
5. Your teacher might be a bit disbelieving at the amount of tears that can be shed. Until they have their own children and discover for themselves how emotionally traumatic the whole parent/child music practice relationship is.
6. A little practice everyday is better than none at all. I have had kids get stuck at various times along the way because they've got bored or found it hard and just saying 'How about you just sit down at the piano for 10 minutes?' seems to help get through those hard times.
7. Don't let them keep practising mistakes. They are super hard to correct - it takes about 100 times through for every time they make a mistake so it is worth nipping in the bud.
9. Practice with them (especially beginners) and when they're older, I listen and yell suggestions from the shower like 'use the metronome' or 'that's a C sharp, NOT a C' (as you might imagine so deeply appreciated by the teenager - not). If you don't practice with them they will only play what they like playing, keep playing pieces with lots and lots of mistakes and consequently avoid what is hard and get stuck.
10. Keep going. It is draining at times and constant. I feel so weary some days at the thought of having to motivate everyone to practice - especially on weekends when I just want to read the paper! But we are starting to reap the benefits of our hard work now. My older three recently played in the music group at church and they loved it, it wasn't hard for them and it was exciting for them to see how they could use their music to contribute (one of my big goals for their music). They have so much fun being in bands etc - but they don't like the practice. Not many people do (and if they do, I try to avoid talking to them!).