Very nice, you got a good eye for proportions. I like the shading you got going on his forehead and cheeks, and how there's nearly a hint of cross hatching on his neck. The only suggestion I have is to have more contrast in the shading in some areas like the ear, neck, and eyes, even if it's not the exact same shade as whatever you're working with. Um, I'm not sure if you're looking for critique or more in-depth suggestions with these, but I'd be happy to provide any if you want.