Tokyo isn’t a city per se but a prefecture. A prefecture is more akin to a county in the US. Japan has 47 prefectures. I would recommend two important cities in Tokyo to spend your time in - Akihabara Electronic District and Shinjuku (fancy) District.

While public transport is great, payment requires cash, iPhone, or Suica cards. Unfortunately, Android phones sold outside Japan do not have the appropriate NFC to pay. There are multiple different types of rail companies operating in Tokyo. When you buy a JR pass (please don’t) or a 24-hour pass, it isn’t obvious where you can use it.

Akihabara

Start the day with a walking tour of Akihabara.

Afterward, check out, Yodobashi Akiba, the largest electronic mall in the world. And the 1200-year-old Kanda shrine.

Spend the evening in the Ameyoko Shopping district. It is great for both eating out and shopping.

I would recommend spending at least a day or two in Akihabara.

Shinjuku

Shinjuku is the fancy glittery city of Japan. I would recommend starting the day with Shibuya Crossing. Shibuya Crossing is the busiest pedestrian crossing in the world.

In the evening, do another night tour to get insights into Memory Lane (Omoide Yokocho) and the night district. Memory Lane is known for its narrow allies and small eateries. Night district is known for Host and hostess clubs!

In a nation of 140 million people, there are 100 million vending machines in Japan. Fairly priced and convenient to use.

Go around Tokyo

Visit the Tokyo Metropolitan Government Building Observatories to see the Tokyo skyline. It is completely free. And you might get a chance to see someone playing Piano as well!

And then check out the iconic monorail.

Note

1. Almost all food labels are in Japanese, so, Google Translate is unavoidable before buying food.
2. Most chains accept credit cards. Most small restaurants accepted only cash.
3. Indian food is easy to find. And since it is targeted at locals, it is not expensive. Indian food is the best choice for vegetarians. Venu and Veg Kitchen were the best ones in Akihabara.
4. Vegetarian rice + seaweed snack is widely available in all convenience stores.
5. Public transport from Narita airport to Tokyo city would cost about ~1100 yen each way.