Glad to see you are working so hard here! I notice for life drawings you are relying very much upon shapes...shapes can be a very powerful tool to use, but in my opinion using construction and drawing through the forms of things is extraordinarily important. For example, rather than use a couple lines to outline the upper leg, instead start off lightly with a cylinder in which the entire ellipse at either end is drawn as though it is made of glass (you can see the other side). This allows you to better understand how the forms sit in space--what volume do they hold, is it coming towards or going away from us, how will it interact with light etc.
Anyhow, keep up the good work