Brixen recommended me to switch to use dvorak instead of qwerty. Although I've never tried dvorak, I've often heard that it is very effective to use this layout.
This pdf is the most important reference for a dvorak beginner of vimmer I've ever found: http://boredzo.org/vi_tutorial/vi_tutorial-Dvorak-Color.pdf
Brixen also told that those lessons are good for learning dvorak:
I input Japanese by kana-typing input style on my US Keyboard. It's independent with qwerty mapping, so there's no confusion about switching dvorak to qwerty to input ASCII typesets.