It's looking good! Keep practicing! ^-^ You've got the hind legs pretty good! the best way I find to learn how to get anaomy is just to study your real pets (if you have any) and just do what's called Gesture drawings. A Gesture drawing is just a very quick like 1 min drawing of the "pose" of the thing you are trying to draw. It's very quick and though it may seem silly (and a bit odd looking) at first it does help! I promise! 8D
Here is a good example a cat gesture drawing!See how scribbly that is? It's just very quick and it's just the very basic shapes of the animal. like I said it seems silly but amazingly it does help you learn anatomy really well with lots of practice.