This post is kind of reminder of importance of inspection of the imaging subject. Inspection the form of the one or another part of face can be done just by touching this face part, or go around of imaging face and inspect it. Use auxiliary lines on the paper, it will help you to construct your drawing. This way helps you to convey a correct facial relief. We use to draw lines of nose, lips and eyes to follow the symmetry and perspective but I think it´s not enough for correct volume conveying.
