Odaiba is a great place to visit. You can get there by a waterbuss that is futuristic looking or by the Train that is quite nice.
It has Joypolis(SEGA Arcade place and has Initial D playable in car!!!) and the mall next to it or in that place has a ramen area that has ramen style from different areas.Near there is DiverCity that has that big Gundam beside it.
Nakano Shopping District might be familiar from Digimonstory: Cybersleuth and that place has a good selection of reasonable prised stuffs if Akibahara is too pricey for you.
Akihabara also have arcades and I recommend trying to find a game where you bash the table and flip it in the end and other awesome arcade games. Also pachinko but those areas are quite smoke filled.
You can go to the sightseeing floor in Government Building free of charge and Square Enix Cafe is quite a nice place but getting there might take too much time if you don't know where it is.
Tokyo Sky Tree is a good place to see the city but to get on the upper point costs extra. Ueno Park is great and has multiple museums near each other.
Foods I recommend are: Gyoza, ramen, okonomiyaki, omurice(omelette with a rice within), curry, crepé(there are lots of selections), katsudon sandwitch,
yakitori and they sell bento(boxed lunch) that heats themselves by pulling a string and giving it few minutes to warm up in Tokyo Station.
Beware that flavor is quite strong and accomodates the ingredients if you are not used to it and they give miso soup as an extra in the morning at some places.
Also. Many places have food ticket machine outside of the restaurant that you buy before going in (no english usually though but some have pictures and you can always check the display if you want certain food in there).
Displayed food looks so real and can be helpful.
Always have cash with you and it's OK to have part of them as dollars in case you don't use all the money and currency exchange is easy in big stations.
Learn the value of the money by hearing(1-9, jyu=10, hyaku=100, sen=1000 and man=10000) and you can rate them nearly as 1 yen=1 cent.
Depending the duration of your trip, focus only on one or two areas for a day unless there was nothing there and some places are good only during certain times.
Shops closes early and they play the song when they close it, so waking up early and going early to sleep is good unless you want to hit the bar or hostess club.
Avoid rush hours when using public transportations. They can get really packed. Buss is cheap but only use them if you know the destination exactly.
Don't bring useless things that hotel provides like a towel, tootbrush and other stuffs.
I recommend having a japanese language app on your phone if you need to ask something specific.
Explore and let your instinct take the lead sometimes.
And lastly. Remember to promote your group by wearing an Easy Allies shirt.
And if you meet an ally please take a photo in those special booths found in arcades or other places.Would love to see it.