I added his pipe and I have started to fill in his beard!
Sorry about the photo quality, I am a horrible photographer!
According to the tutorials that I have read, the first step to drawing facial hair is creating the skin tone beneath the beard by making circles at varying sizes and shades and then using a stump to blend them. Then using a kneaded eraser, you lift some of the graphite to create lighter areas.
Next you begin to layer in dark areas and light areas with different leads to begin creating the fullness. Do not press too hard because later you want to add highlights with your eraser by removing some of the graphite. I am rewording what I have read, the tutorials available via an online search will go into much greater detail than what I have listed.