Really great start. I say start because I think you can do some more work on this to make it even better. You mentioned that you used a variety of shades, that's very good that you're aware of that concept, however you need to push it more. If you look at the scale I've included your drawing only has values within the first two or three columns. Ideally it would have values that span the entire scale. You have a solid base to work with and one of the hardest parts of portrait drawing is being aware of value and how light plays off of a face. Take a look at this image [url=http://cdn3.vox-cdn.com/uploads/chorus_image/image/4877501/lightning_returns_final_fantasy_13.0_cinema_640.0.jpg]here[/url] and blur your eyes. Use that as a start for where your general values should go on the face. I really like it so far! Keep it up and if you do put more work into this one I'd love to see it. Here are some more resources if you want to learn more about portrait drawing. It's one of my favorite areas of art so forgive me if I rambled. [url]https://www.youtube.com/watch?v=SBP1_v0wn1I[/url] [url=http://books.google.com/books?id=rvRYad5MwIIC&pg=PA40&lpg=PA40&dq=drawing+value+in+portrait&source=bl&ots=JYAZXwI5wY&sig=YF0zfoRsctRQAQVFXk_pWq_MvY0&hl=en&sa=X&ei=RmpLU9TePMfQyAHoqYDoCg&ved=0CH4Q6AEwFA#v=onepage&q=drawing%20value%20in%20portrait&f=false]Here is an entire book on the subject[/url]