Try to think in terms of shapes first. The foot is much like a wedge or a door stop if you’ve ever seen one. A wedge has distinct planes. A top (which is where the lower leg meets the foot) then from there the wedge tapers down and out.(Think the bottom of the foot is wider than that round ankle at the top of the wedge) The wedge gets thinner as it goes forward towards the toes. Drawing this wedge is much easier to do and after you get the perspective correct, then you can start adding the details like toes and nails etc. I hope this visual helps you to understand how to break things down into shapes.

