Trying to improve at paiting clothing and fabric. Feedback would be appreciated

These are some rough sketches from yesterday. They were done pretty quickly, with the longest one (number 3) taking about 30-40 minutes.
My main goal was to keep things simple and try to establish decent shadows and form using a relatively small number of broad and confident brush strokes. Although they turned out pretty messy and i feel like it's pretty clear that i didn't know exactly what to do to set things up.

There's also a couple random poses in there that i did while warming up, but my main focus is on creating better shadows and light on clothing.
Some notes for each sketch below.

Number 1: This one was intentionally done with no color. Usually when coloring a white shirt like this i would start with a very de-saturated yellow or orange, and add some subtle blues in the shadows for ambient light. This one was meant to be an easier warmup sketch so i just focused on values.
I feel like the shadows look a bit unnatural. I'm not sure if softening some of the edges might help here or if that would make the shapes too vague.

Number 2: I was focusing on simplifying the shapes a bit and trying to make the general forms of the jacket clear. Although the shapes are pretty messy (especially on the right sleeve). I tried to do some of the lighter shadows on the right sleeve by starting with a darker shadow and adding ambient light but i don't really think it's working.
Other than trying to have cleaner more accurate shapes, I'm not sure what else i could do to improve this one.

Number 3: This was easily the most difficult one for me. Again i was mainly focusing on trying to use relatively simple shapes to establish the form.
Looking back at it now, i see that I could have put some stronger ambient occlusion under the collar and where the sleeves meet the torso.
But more tips on this would be much appreciated.

Thanks!