for school we had to draw a person, in my case it's (supposed to be) Megan Fox. We had to follow a certain technique to shade it.
In the WIP picture that I uploaded, you can see this=)
Oh also, the reason why you can still see some guidelines is because I shaded it on a copy of the line-art. So I keep the original as line-art only=)
I hope you like it, comments are welcome!