Loving your studies bud awesome work.
I’m no expert but the key with folds I believe is find your point of tension. The folds radiate from there, often finding the next point of tension. If you’re not up to it yet I recommend watching the clothing lesson. As always referencing is important, especially when starting out.
Also one thing I try and do with shading is I shade the clothing as a whole first, this gives it form, once you’ve done that then you move on to shading the folds and details. With your clothing on the girl, although you get a sense of the folds, it’s hard to get a sense of the form if you get what I mean. Hope this helps.
