Wow! Great expression on the face. i can tell you are good at faces. ok to start off with I think it's great that you used lines to shade some areas of the character. But I feel you could have a done a little more of that in some areas like underneath the neck where it should be darker. I believe the light source is coming from the right so the shadow under the neck would be on the left a bit more than if the light source would be from above. I also notice the different line widths in the character you use a bit bold on the darker parts and then you use thinner lines in the areas where it's lighter. Although I wish you would use a it more line width in the character. Just a bit more. I also love the texture in some of the hair. Over all great sketch of a person.