Skeletons/component shapes are a fine exercise to work on! :) But of course you're free to try other exercises if you have a different goal in mind. What you've accomplished with self-teaching is very impressive!
Your longer drawings look beautiful to me. I do notice that you have a tendency to really "pet" the lines and go over the same area many times with more and more and more little strokes. I would recommend focusing on trying to capture the gesture with the smallest number of long, fluid lines possible in your next few practices, to start to get a more fluid and confident look in your figures.