Okay, I have sat here for 5 minutes now, and I just honestly love this picture. Great lighting, wonderful subject, so original, and very fun to look at.
Your aperture, shutter, etc were great, and it looks like your score did fairly well. I personally think it should have been a bit higher.
As far as changes - maybe brighten it up a bit, and show more of the pencil. Also, if you look at where the broken pencil is, it did not just complete a line. By placing it at the end of a line or sketch, it would look a bit more realistic.
Overall a great shot, very original, and well done!