Magic

Z to zoom in to see the detail.

Peep some of the process in the ATTACHMENT.

See the full size illustration and article HERE.

Sometimes I'll skip the redrawing and work straight from photo reference (only if it's my own), but I prefer to draw things out to gain a better understanding of the form. Drawing things out also allow me to make optical adjustments and create my own emphasis without being dictated purely by the lighting and composition of my photo reference.