/ic/ - Artwork/Critique

Any resources that explain what makes shapes look good? People are talking about making the abstract shapes that form the work look good, about how good painter is a good designer etc. but I can't find something that would have guided my decisions. I understand that it's important to menage your tangents and to make silhouette look clear but aside from some other stuff that I can't remember right now it's mostly a guesswork.

For a specific example: let's say there is pic related, girl with gorgeous hair, and i want to depict the feeling of it while not copying it pixel by pixel. What things should i pay attention to to ensure that the end shape is aesthetically pleasing as well as retains some of likeness?

Second question: anything on simplifying stuff? I'm beginning to understand that determining what should and shouldn't be depicted is important but aside from values/contrast/"business" of things I can't quite grasp what should I be aiming for. I'm sorry, I know I'm not forming the question in the best possible way, but like what questions should I ask myself when i want to depict something, how do i decide let's say the thickness of line, or how much of a curve should be there etc. Anyway, thanks.