The only thing that comes to mind right now is to copy out of a Japanese book or newspaper or something and say the words as you write them. Incidentally this also works with computers. I used it to help me with 闒懦 (ta4nuo4; it's Mandarin, and means "having a low status and being weak and 無能"... sorry, couldn't think of a good word for 無能 offhand...). Really, the thing that will help is repetition, and it doesn't really matter so much how you get it so much as that you get it.