You want to learn how to draw.
Then Do Not Start off drawing manga. Simple as that. Look at anatomical drawings and other referances of semi realistic pictures. Too often people start of trying to draw manga stuff and never progress beyond a certain level of skill, it ends up being pages and pages and pages of annoying chibi's. Good manga relies heavily on shadow, shading and style, not just the line adrawings that so many people who "draw manga" come ut with.
Sorry thats my persuasive rant because I do get sick of lots of people just drawing stupid amounts of chubi's, getting mixed up between Manga and Anime, and generally following a huge trend without the ability to do it well.