Oh how fun!!
Eat and experience as much as you can! It should be a great experience.
I like to recommend the Shibuya area of west Tokyo if you’re there on a Sunday. Depending on the weather, something uniquely Japan is the Rockabillies dancing in Yoyogi park on Sunday. They are quite fun to watch and are very passionate about their style!
Bordering the north of the park is the Meiji Jingu Shrine, which is also uniquely Japan. In this area, you have the city bustle and Kawaii (cute) culture of modern Japan nearby on Takeshita street to the east (also fun to see), the Rockabillies right next to it on the west in the park, and then right next to the park just north is the huge, quiet, serene shrine where city sounds begin to melt away and you are surrounded by ancient culture and forest. It’s one of my favorite places to visit.
Also, if you get a chance, consider seeing some other prefectures and some of the surrounding rural areas for an interesting contrast from Tokyo’s high-paced life.