Uhmmm.....I'm not good with explaining things much but....uhmm for the hair, you put a light color (lighter than the original one), and draw some little lines like I did, and then use the Highlight tool.

And for the folds, first you use the very-soft-light brush (sorry but I don't know how to explain it^^;;;) to color allll the shadow parts, and then use the eraser brush - which has the shape of a dot in the middle - to erase the color that you don't need, and use different kinds of brushes too, you might wanna try out how those work^^..and that's how I did.....

I'm sorry if it's not easy to understand. If you want a tutorial-like picture just tell me, I don't mind ^__^

And thankyou so much~! \(^o^)/