Let's get into shading a drawing! We'll explore form, planes and light on form. I'll guide you through making an object feeling 3 dimensional by indicating the elements of light on form - highlight, center light, halftones, core shadow, reflected light, cast shadow and occlusion shadow. How the local value of the object effects the tones. And how does intensity of light affect tones.
Summarizing Andrew Loomis's approach to drawing the head. It's a great method for drawing the head from various angles. Draw the head from the front, side / profile, 3/4 view. Learn how to add an up or down tilt to the head, left and right turn, and a twist.