From a very early age, you should be teaching music appreciation. If you're a parent trying to get your child interested or want to keep your child interested, you have to express music appreciation yourself.
You don't need to be a music expert. But you should always have music on in the car and in the house whenever possible. When you're together listening to music, have a conversation about it. Ask your child what he/she thinks about the singer, the piano, the beat, etc. The point is to surround them with music and engage them. Get them to think about the music.
And play quality music: jazz, classical, and some pop. Keep away from the rap and hiphop!!!
I have so much more to say but I don't want to monopolize the hub space! You're welcome to write me anytime.