This is actually a critical stage.

Things start to look like something at this point, but it's kind of hard to tell when you're working on faces. That's because before they start to look like the picture you have to build them up and for a while you just have to trust that the foundation drawing / outline is correct. Until all the shading is done, it is not going to look like it's right. It's a little nerve-wracking, waiting to see if you're doing it right and the person is going to look anything like the picture.

Tonight I switched from the lead that I've been using primarily, HB, and used a little bit of the 2B and 2H.
The 2B is a little softer lead (it goes up to 6B) and lays down a darker line. The 2H is harder and will give a lighter line.
I will eventually go all the way up to 5B (the softest I have at the moment; someone must have eaten the 6B). That will really draw out the depth and give it a more 3-D feel.

There's a bit of a glare on the surface (I finally brought my swing-arm lamp over because I'm getting into more of the delicate detail and couldn't see what I was doing very well), but you can see the detail starting to come out in the faces compared to the previous picture.

(by the way, I am drawing this on Crescent Hot Press Illustration board, #215)