There’s a component of kids making art that isn’t always connected to adults doing it. We often see art making as work. Children just see it as play. Or, probably more accurately, they don’t think about it as anything, they just feel like creating stuff and do it.
It’s so easy to get in our own way, worrying about our skills or motivation. We fear the reception of the finished thing won’t be good. All that gets in the way. This is another case where focusing on process or praxis can help. You start something because you need to, and damn the finished thing that happens somewhere over there, beyond us, outside where we can see.
Once again, we may have a map: an outline, a sketch, a chord chart. But the path can always deviate, and you may or may not end up where you planned. It doesn’t matter. The hardest part is starting—the premise of Wonder Boys aside—and getting into kid mode might help you do it.