We visited the Tokyo Metropolitan Government Building to view the city. It's free to visit, and it has a north and south tower. There's also a cafe at the top, so you can grab a bite to eat and shop for souvenirs. They also have a stamp there if you want to fill your book.
We randomly ended up at Totoya Izakaya restaurant for lunch. It was a quaint little restaurant that served only two meal sets eel or grilled fish. It was a great experience dining at a place locals dined at. They didn't speak English but were very welcoming and a guest in line helped us communicate. They pointed to their handwritten menu on the wall which only had two items.
For dinner, we tried to get tempura but the restaurant couldn't accommodate us since it was near closing time. So we searched on Google and ended up at Gyopao Gyoza Shinjuku cause of all the great reviews. Some of the dishes were pretty good, but it wasn't as good as I was expecting based on the reviews. The place was full of tourists and the food was a bit pricey. IMO I don't think it's worth a visit. It seems that tourists use Google or Yelp but locals use Tabelog. So use what suits you best. Some of Google's suggestions fell short for us.
Shinjuku is a great place to walk around and Golden-Gai is a great place to get a drink for adults.
Tokyo Kabukicho Tower is another great place to visit for food and drinks.
