Peter,
This will be a major obstacle for me to overcome. When I draw, the darks seem fine, but when I stand back and look, and especially when I see my work on the computer, it's too light. I try to overcome this, but I end up over-working the drawings. Maybe I should be using conte instead of graphite.
I'm open to suggestions. I have tried filling the grain of the paper by using a stump, but that was disastrous. For this piece, I went over the hat and hair excessively, and even added charcoal, and I felt it made it worse.
Tell me what to try, and I'll try it. The photocopy idea is good, if I can sneak a few copies past the boss.