I’m a musician, but it’s the same for artists: you have to do it over and over and over, and eventually it starts to get better. No matter how old musicians get, they still practice those fundamentals - scales, chord progressions, intervals, etc. The idea that a musician just improvises beauty out of thin air is mostly an illusion. It’s really the product many, many hours of practice.

You want to sit down and create a work of art right out of your brain, but the reality is that most good art is the result of years of mastering the fundamentals, and then several drafts before it looks right.

I spent years playing scales, chords, riffs, etc., just to get to the point where I can improvise a plausible blues solo. I don’t know how I stuck with it for so long, but the feeling I get when I can just grab my guitar and play along is so satisfying that I’ve never doubted that the effort was worth it.

So start now, working on the fundamentals, and practicing various techniques that you need for specific textures like hair, or drapery, or eyes, or trees, or clouds, or shadows, etc. When you can do all those things well, you can bang our something credible when the inspiration hits you.