In about 2 years once I finish high school. I want to experience all Japan has to offer, from traditional inns to modern entertainment. I want to be able to communicate the best I can with though. Since I do have a couple years to learn it, what do you suggest would be the best way to start learning? Online sites, textbooks, dish out the dough for classes? I work at a Japanese restaurant, so thankfully I could always have my boss help with my pronouncing and wording...

Also, just so I know, what are the things I SHOULDN'T do? (Things that will scream I'M A TOURIST)