I agree with Symphonic Trance that learning anatomy first is crucial.

My first "anime" drawings were in elementary school, when my friend first introduced me to Sailor Moon, and they were unbelievably bad. =D
I wasn't able to draw anything worthwhile until I stopped copying manga, took some art classes and tried to understand the human figure--then went back and stylized from there. (Although my anatomy is still far, far from perfect, my stylized drawings have improved immensely.)