I'm just a beginner, so you are much more advanced than me. I think this looks great. You are very good at eyes. (I also like the drawings of Morgan and Yoni that you posted.) The main criticism that jumps out at me is with the shading of the background. To me, the background is too choppy and stringy. It has too much of its own texture and is competing with the rest of the drawing. Sometimes, at a quick glance the background even looks like long stringy hair. I think it would look better if it were a smooth, blended gradient that doesn't call attention to itself.

I was (and often still am) in the same position. What started working for me was to draw the same pose over and over, constantly correcting the proportion errors. Once I got to the point where I could do a decent gesture three times in a row, only then would I move on to the next pose. My personal tendency is to make people too wide and stocky, so after making the same mistake over and over, I started "seeing" how to make my gestures more narrow and graceful. What also worked for me was to ignore the clock. When I would attempt a 30-second pose, the only thing I accomplished was to create a terrible drawing very quickly. Now I take my time and really think about where the lines need to be. My 30-second poses take five minutes. But after I've done the same pose a dozen times I find myself getting faster and faster.