Back to the sketching routine, these are some of the recent sketches I have done on public transport.
"Heads are obviously rather complicated to draw. However, if you think of them as a compound of many shapes and sub-shapes, you will realize that you can draw any of the individual parts by analysing them carefully first.
I stress this structural approach in your thinking about the head because most beginners overlook these basics in their preoccupation with drawing the features. This reverses the proper order of the drawing process. Until the structure of the head is established, and the lighting determined, the rather subtle details of feature, such as the placement of the eyes, the length of the upper lip or the width of the nose will have no form with which to relate" - Paul Calle on heads in his book "The Pencil"