I love your ability to capture the shapes and movements with the subject! The shading also gives a very nice looking rendered appearance. I specifically love #17! What I would suggest is focusing more on your weaker spots whether it faces hands or feet! Rather than focusing on the things that you already have a fairly good grasp on (being form). It's extremely important to balance the subjects you practice!
You have a lovely ability in capturing the dynamics of the poses and I can really feel the weight distribution in the figures. I would just suggest defining the hands and feet on your figures a bit more as they can be really important in capturing the expression and emotions of figures. You actually do this really well in figure 15 with the placement of the thumb on her hand or showing how she places the weight on the ball of her left foot.