You've got a great start, especially with the still life studies. You keep doing that non-stop and you'll see the effects of those studies in all your artworks (Color/Value/Framing).
For Michael Hampton studies, I recommend that you balance copying his work with applying his principles on actual studies. Copying his works will ensure you understand what he is communicating, but it's not enough as you are only replicating his simplification of the real figure. Next step would be to take a reference image of a nude figure and break down the body in to similar boxes/cylinders to really translate what you learned into application!
Also, I noticed that in your color studies you mostly use textured brushes. They end up giving some muddy colors and forms. I would recommend that you try to achieve your color studies through the basic photoshop brush, with pressure sensitivity for the opacity for blending. And just used that basic brush to nail the color/values of your studies.