+' Improvements '+

It's a little late but try not to do pillow shading, which is when two lines of the same shading meet they'd form a darker shade, I know some ppl use this but it could a help little more.

try creating a colour palette before making the skin or try making the skin unshaded before shading it.

try a colour themed skin so lets say a red or a pink-ish red theme? if the hair is trying to be blonde try making the hair light pink or a cream or if its suppost to be black make it a sort of dark navy. if brown a lighter navy or dark red.
make the colours of the clothes like a blue, pink, cream, red and burnt green if its floral.

you could try learn hueshifting! (i know someone down there already explained what it was, but for a more in-depth explanation, it’s where you shift the color wheel to the right (shadows) or left (highlights), to add more color and interest to the skin. like for example, if you’re shading orange, you would shift slightly to the yellow to create the highlights and to the red for your darkest shades).

also, learning off of others’ styles is another great way to improve your own shading. take parts of shading you like from other people and try incorporating them into your own style, along with credit of course (and you should also ask the creator permission first if you can take inspiration from their style).
hope these tips help

Honestly, I'm not the best at shading either, but I can try-?
Like lavender said, maybe some hueshifting would be fun, and a bit more difference between dark and light areas.
I looked through your more recent skins, and I think u might be able to use a bit more of the outer layer for depth and detail, and a bit more overall lighting?
I find taking inspo from others' skin shading is also very helpful :)

Ooo idrk how to help but
How I improved was honestly just taking inspiration/looking at other people skins
And try experimenting a little and just go crazy
And practice ofc XD

try leaning hueshifting! it's where you change the colors of the shadows slightly, for example, pink would have more of a purple shadow, and more yellow-ish highlights. this video has some good tips for colors:
https://www.youtube.com/watch?v=7Ela_dNMBjc
also, Jingles' other tutorials are really great as well!

Ok join my skin tutorials and be notified each time a new shading tut comes out
>> https://www.minecraftskins.com/skin/23096775/skin-tutorials---notification-sign-up/
Lesson 1 is out already:
>> https://www.minecraftskins.com/skin/23097208/lesson--1---hair-shading-tutorial--simple-/