Feet-this pin is good because it shows you how to draw feet. Its also good because it shows you how not to draw feet so you can compare it with your figure drawing to give you an idea of how to improve your drawing to see if it looks good or not.
Make it a challenge to draw most or all of these. Use as inspiration to take photos of themselves with their phones. Draw onto tracing paper or acetate, try layering, continuous line, blind drawing, left hand etc to build portfolio