I think your work would really benefit from having stronger values. Right now a lot of your values are close to one another, more towards middle values, and pushing them would help showing forms better and make it easier to read your pictures.
First, defining the structure will help you define the values better. I find starting with defined color changed and then belnding them as needed makes it easier.
It could look like something like this
And then you can blend so that the value and color change aren't so drastic.
Also the environment will influence the colors of the object in it. So since she is surrounded by a deep blue sky, you probably want to add some of that color in the shadow areas and the surfaces facing the sky. It will help make her blend better with the environment.
I hope this helps and keep drawing