I give this sketchbook assignment every year to all my art classes, from beginning to adv. There's nothing like shoes to help students learn how to draw. The first two photos were made by two of my Art 1students and the last one is by an Adv. student.
I only allow pen drawings in their sketchbooks, I just don't like pencil in those books, they begin to smear after a while, even after spraying. OK, the real reason is because I don't think there is anything prettier than a pen drawing.
The top two drawings were done with a sumi brush and india ink.