Help

This is a composition I am currently working on that is still in a very rough stage right now...I am looking for tips on composition and how to create more contrast between the characters in the painting without having to completely repaint the figures that I am happy with. It seems that I can't quite add the shadows I'd like and make them blend properly with the alreay dry skintone that I have painted already. Any suggestions/comments are welcome.

Thank you

Elijah