If there is a class available for anatomy, then you should consider taking it. But studying books on your own will be just as helpful. There's probably a ton of free online resources too.


These might help
7 Tutorials on How to Draw the Human Anatomy / Body / Figure | Drawn in Black

Studying styles of manga will help a lot. It will give you a good understanding of how to stylize things like the human form, or animals, etc, making it easier for you to draw a lot of frames. Does that make sense ? I'm bad at explaining...

I would suggest practicing drawing different things from your favorite manga, like chapter covers, without tracing. Eventually start changing things about the characters. Their hair, facial features, and poses. I think that will give you some good practice.

I hope that helps.