Correct me if I'm wrong, but are you doing the characters from 7 deadly sins?
Composition wise this works pretty well so far.
Light is linear. I recommending using a 3 point light set up. it seems like you have a top left sun light. With them being outside I assume, you can have the blue sky light coming directly from above and the bounce light from the grass coming directly opposite from the sun light. The bounce light will make it so your shadows on your legs have a bit of a green tint while the top of the character to have some blue cool tones. Besides the lighting, I think the anatomy needs a bit more work for both characters.
Hopefully that helps.