Personally I don't find things like the Riley method very useful, at least not in practice. I myself am more inclined to focus on volume and shape (then again I have a background in animation, so that comes with the territory.)
Something that might be helpful in your studies, or in trying to understand the mechanics of the anatomy, is to stand in front of a mirror and just observe yourself. Just move your leg around and try to look at it from different angles, you'll get a better sense of the 3 dimensionality of it.
I'm assuming you use mostly photo reference in your studies yes? While they are an excellent resource, they lack that actual depth you need to really learn how the body functions.
This artist over on instagram has some great tutorials on how to simplify anatomy
https://www.instagram.com/emiliodekure/