I'm actually studying hips more now, I want this to be somewhat of a resource thread for hips.
The important thing is to just know the major muscles/bones. Anatomy takes a LONG while to even get a rundown on. Knowing muscles, bones, and how they interact change the appearance by even the smallest movement.
Don't be in a rush. Like what other anons said, study other artists, do copies, master studies, etc. It helps having an anatomy resource to see why the artist drew that part of the body.
Obviously, don't just copy. Make stuff from imagination so it can stick in your head.

TL;DR: study artists, copy them, make stuff from imagination, read anatomy books, etc.

Pic related is a good artist to study, he has a lot of anatomy studies that are expressive when it comes to the female body

cyjalway is pic related.