It may be that you need some measure of talent. In my case even tracing something ALWAYS turns out different from the vision in my head. Trouble is when I ZOOM in to the vision in my head, the details are never clear, and no matter what I draw, it looks wrong. Give me a technical drawing and I'm good. Art just isn't my thing.

Having said that, you can look at some (even expensive) art, and it looks like it's been done by a child, but it sells well. Art is in the eye of the beholder, There no way to determine good art from bad art ... It's all art, and somewhere there's someone who will like it.