You'll probably hear this 100 times over, but the best way to learn is by practicing. Draw anything and everything around you. There are way too many books to narrow down. I recommend anatomy classes, even if you're drawing non-humans, learning how muscles and bones interact was invaluable to me.
There is a book if you want to draw clothing and whatnot-Dynamic Wrinkles and Drapery by Byrne Hogarth, he delves into how things fold and how the flow can be expressed.
If you love it, keep with it. I never believe my stuff is any good, but artists tend to be their worst critics.