Just cover all the touristy places first. Then go to their bookstores and get those Japanese travel guides if you have something in mind. Their guides are very useful and comes out seasonally, with all the best places to go to and lots of nice pictures. You going during autumn right? It's my favourite season. Go to Takao-san for a hike if you like the nature. Visit Kyoto for a weekend using the bus. There are lots to do in Tokyo too. Make some friends with your class and go out together. I'm sure you will have a blast and will not want to come back. Hahaha..