So how do you guys learn Japanese?

Without going to classes, that is >_>

lol, at the moment, I'm still in high school so there aren't any Japanese courses available, and I really don't want to be spending my saturdays in class to learn something that would only really be useful if I have spare time to actually PLAY the visual novels. I know about AGTH and Atlas (which I have attached to Kanon right now), and I have a kanji-romaji conversion site, but I just wanted to make sure I'm going about this the right way. Basically, I figured I should start by learning romaji and hiragana, and then maybe I'll pick up enough to understand more than the engrish from Atlas. However, are there any ways to translate a sentence from romaji to english with a definition for each word, or is there anything in particular I'm missing? I know this will take a lot of work, but I'm hoping to at least get a start now so it can start paying off in my adulthood (I don't exactly want to learn Japanese by the time I graduate university and lose interest in anime a couple years later).