I don't have any experience with it, but if I were you, I'd do this:
First off, I'd study birds. All birds. Finches, eagles, flamingos, chickens... Especially their face and wings. And perhaps legs. Draw at least 3 different poses of 5 very different birds for starters. I think that ought to help you a lot.
Then try drawing human arms and shoulders and gradually morph them into wings.
This ought to help you with the bone structure.
Then, I'd combine the knowledge and practice and draw what you want.
