Ah yes, I have a book by Vilppu lying around, I should try to look into it.
I'm still doing Loomis exercises right now and I plan on reading Hogarth and Bridgman next.
In terms of animation I've gone over most of the disney material for study (Robin Hood and Sleeping Beauty are very simple and good to study) and some of the flexing tubes era. I also found it nice to study how anatomy and muscle deformation is handled by more recent cartoons, such as the pretty decent "Spectacular Spider-man".
I'm making progress, but I still have trouble putting it all together. I might search for some new life drawing classes in '10 to apply the newly learned techniques on live models. When I was doing life figure drawing, I was still in my contour drawing stage.
What you describe about your life drawings class seems to be contour oriented too. It's good to learn how to interpret masses to contours before starting the theory. That's why the beginner classes in life drawin tend to leave you to your own devices, so you can get acquainted with contours. It's not advisable to do volume study before you know most of the theory, so shading should be left out of those exercises.
As for the drawing you posted, have a look at the mouth area. You oversimplify the way the mouth connects the chin. You can draw a triangle from the mouth corner to the middle bottom of the lips to the chin. That part forms a plane that is not represented in your drawing. Here's an wireframe construction of the nose and chin areas that might be interesting. The nose area I did is not really correct, but still, look at the indent in the middle. There's a fat mass there that needs attention, which runs into the mouth area (represented in green).
