My advice: Start from the basic stuff. Then challenge yourself and try to translate at least 3 short stories to Japanese. That will make you realize the words you need to learn to express yourself and will help you to talk with Japanese people. Of course that conversations happen naturally, but sharing stories effectively is a powerful way to let people know you better.

If it's even possible to learn a language, especially languages like Japanese, in 6 months, you would have be buried in textbooks every singe day. Being fluent and knowing enough to get by in Japan are two very different things. There are people who go there knowing zero Japanese. Japan has become very tourist friendly over the years. As long as you can read signs to find your way around and read directions, you should be okay. Probably minimal conversation skills for asking for directions and buying things at stores.

Hahaha,,,I have the same needs, because I plan to visit Japan during this summer. But I just finish the 50 sounds and start the beginner class...