You draw it by drawing it.
Don't bother with the western way; after all, when is the last time you've seen them draw cute stuff like that? Avatar? Totally Spies? Exactly.
Japan is a nation of robots. They have no creativity, they only know how to follow and copy what they like. They learn to draw by copying the pictures they like most until they're able to draw themselves, and then they get some references and go at it. When you've drawn something enough, you'll understand and be able to draw it by yourself. It's all about training the eye, the hand, and the mind.