Hey, thanks so much for the diamond!

I'm not that great at shading clothes, but I'd suggest putting highlights of a slightly lighter shade on the outsides of the skin, like near the shoulders. I'd also suggest using a a darker shade with more transparent brush, like at maybe 50% see-throughness, for the shadows.
As I said before, I'm not that great at shading, but that technique has worked well for me.
I also think the way you shade hair is very good.

Here's a tip for your struggles: Make it lighter where the part of the clothes are higher up or stick out.
For example, the cuffs of a sweater stick out more than the stomach area, so you'd make them a lighter color.
I do definitely think your hair and skin shading methods are good!
I hope that helped at least a little lol

looks great tysm for crediting me