Languages are probably best learned by immersion. Short of dropping myself into Japan and forced to speak Japanese every single day, I think watching anime and Japanese drama with Japanese Subtitles would be the most effective and a subconscious level exercise on the learner. This does require complete knowledge of hiragana, and shape recognition skills (kanji are dumb if you can't see tell what they are). Some kind subber might sub the japanese into romanji, in which case, I would need to be a quick romanji reader and hope in a million years that I don't have to actually read Japanese but only need to speak and listen. Eventually, I hope I would get to a level where I feel subs are for dummies, and I can just go raw.
Would be nice if someone can tell me where I can find Japanese Subs though...