Well, you really should try and find your own style of manga art, but youtube has a ton of great references. You can also try and study the art of mangas and animes while you read/watch them. And the manga Fall in Love Like a Comic has a How to Draw Manga Mini Guide in the back of volume 2, I think.
Well, like other people say, you should try making your own style of drawing. However, there is a person (my idol) who teaches how to draw manga via the interenet and in his book called "Mastering manga". Here's a link (i think): www.markcrilley.com