Surprised there is no mention of the Sketch feature so far. That's very powerful! I do art on the side and I know no better of getting the result I want than passing in a first draft sketch.

I super encourage others to learn just a little bit of art technique and your images are going to go to the next level. You need a little construction, perspective, gesture, anatomy, and you're pretty much off to the races.

Knowing names of illustration styles is great too. Look up "style transfer" if you are not familiar.