Buy a book and/or hire a tutor. Visit your local bookstore and buy a Japanese phrase-book. It is helpful for learning the basics of language, and acts as a reference for common words. The phrase-book is generally found in the Travel section, beside the Lonely Planet travel guides. In addition, hiring a tutor gives you valuable one-on-one practice.
Join Livemocha and sign up for Japanese courses. Listed as one of the best website for learning a language online by the New York Times, Livemocha claims to be the world's largest language learning community. You also receive feedback from Japanese speakers, for free, on your speaking and writing skills.
Get a language instruction software. There are two major options in the markets, Rosetta Stone and Tell Me More. Their advantage is that they are interactive, which can be fun way to learn. Although interactive software can be fairly expensive, they are a good investment if you are serious about learning Japanese.
Sign-up for Japanese language exchange (see Resources). Language exchange lets you to practice with a native speaker for a small fee. Alternatively, try to find a Japanese language partner at a local university.