It's looking good! I think a good focus point would be the rhythm of the spine. The model's spine arches back. In your illustration the spine looks a little bit flat, with the torso and pelvis both facing a bit too forward. Try an illustration with some exaggerating of the curve spine and see how it comes out!

I think a good opportunity for you would be to try to unify all of the individual parts. Each part is fine on its own, but as a gestalt it appears abit uncanny and out-of-perspective. Perhaps you can do some 3d sketches of cubes, and study how the mid-points and thirds of cubes look in space. Bridgeman's cuboid faces are amazing for learning how to space things properly. Kudos on your shading and use of value! It is very strong!