Your drawings of poses and forms are definitely improving. However, I think from looking at your past work, you might be sabotaging some of your angles and perspective when you color them. I don't know if you have a pen tablet or a way to do line art on them, but even if you had pencil, I would make it as "clean" as possible, with very smooth, prominent dark lines. Then start with a color base....just even flat colors. Then imagine there is a point of light in the room, and (what I prefer), is to start doing hard line shading, basically cell animation style.
If you use soft gradients like you've been doing, I think it starts hurting the depth of the drawing. My 2 cents. Keep going though. :D