My band was lucky enough to win an all expenses paid trip that allowed us to play at the Tokyo International Music Market, national radio play, a film clip and numerous other shows around Japan (between Tokyo and Osaka).
If you can get an interview on radio, it always helps. We did an interview in Tokyo (J-Wave was the station) and another in Osaka (can't remember the station). But the biggest thing is playing in front of the largest number possible.
The music market was the one of the strangest and best things I have ever witnessed, but there was 6000 people there and they all really get into music they have never heard.
If you can play at Chicken George in Osaka, do it. That place apparently always sells out regardless and sounds great. Also see if you can play with an act that is already known over there even if they sound like anime pop (they will bring a crowd). After a little over a week there, our iTunes sales were beyond what we even imagined.
Also visit a few guitar stores in tokyo. Ishibashi is amazing, but floating around are little stores that sell things at stupid prices. I got an RV-3 and Carbon Copy for roughly $15AUD (for both).