Hey dont be embarrassed by your work, we all start somewhere, keep practicing and you'll be proud of the improvement you see, I hope you keep it up. Take a look at some Loomis books if you haven't already, its a good place to start. Nice work with your anatomy study by the way http://www.placidchaos.com/AM/index..../andrew_loomis
For the perspective, have a look at the leg, standing on the ground. Don't use the leg that is raised to find the horizon line. Don't forget to post the name of the person who drew the line-art.
Very cool that you're already working on your anatomy. Try to break things up when studying. For studying the muscles, concentrate on on part first and go the next one after that. Do life drawings to study the different proportions. Loomis is very good to start with.