Steve,It looks to me like you have the darkest values dark enough - the eyes, nostrils, and corners of the mouth. Your half tones are flat though. You need a wider range of values in these half tones to give all the shapes more form. If these values look basically the same on your reference photo, you should exaggerate these tonal differences. I can't tell the direction of the light in your drawing. That is why everything looks flat. From the shadow under your chin, I am guessing it is from the upper left.
Think of the head as a ball with one light shining on it. This ball is much like the earth. It has hills and valleys - like the nose, cheeks, and eye sockets. As each of these planes gradually curves away from the light source, they will appear darker. As it curves toward the light source, it will appear lighter. The only areas that should be bright white are the highlights that directly face the light source.
I gradually build up values by using softer pencils. Take a softer pencil and add more tone to any areas facing away from the light source. You can blend these values to with a tortillian. After you darken some of these areas, you may need to go darker on your darkest values also. For me, this is always an on-going process. One change effects everything else. I have found that layering the graphite to build up values is usually better than trying to acheive the darkest values from the start anyway
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If you post the reference photo, I'm sure all of us would find it easier to help you.
Good Luck,
You are well on your way to an excellent portrait.
J. D.
J. D. Hillberry
http://www.jdhillberry.com
