One of the ways we unwittingly destroy motivation in children is by teaching them that there is only one right answer.
Usually, in music and in life, there is more than one answer, more than one approach. When children are allowed to explore all the options available to them, they can take personal ownership of them in a deeper way.
Children are more likely to engage and commit to something they have discovered on their own. If they are allowed to experiment and realize for themselves what is good, effective, beautiful, they are more likely to engage with it and remember it long term.
Because beginners don't know the technical skills required for getting started, these must be taught and practiced. By necessity much of this teaching is done in a "do-it-this-way" approach. But this rule-based way of doing things needs to be replaced as quickly as possible by a more exploratory framework, or the creative soul of music is dulled.
Moreover, many children are perfectionists. They already assume without our telling them that there is one right way, and immediately feel like a failure when they don't get it. That's a sure way for them to lose motivation and stop practicing.
By recovering a spirit of invention and exploration, you can overcome this loss of motivation. By changing the framework. you will make it easier for your child not to assess self-blame, and eliminate the fear of doing it wrong.
Letting your children invent is an important life skill. They will use it not only in music, but in every other area that they are trying to learn and master. By framing goals in terms of creating, exploring, and moving toward what is good, instead of only conforming to what is correct, we establish a long-term mindset that guarantees true devotion and love for one's work.