Shinjuku is the best area to stay in Tokyo for first time visitors because of its convenience. It's so busy and what Shinjuku can offer is similar to Shibuya I don't go there too often, but I truly recommend you to get a hotel there.
Shinjuku is one of the biggest transportation hub which enables you to take a day trip to Hakone and Mount Fuji and also to get to any sightseeing spots in central Tokyo. Despite of its great commuting options, you can even walk to great sights like Shunjuku Gyoen Park and Tokyo Metropolitan Government Building.
JR Shinjuku Station is so big that it has 7 different exits - South, New South, South East Exit are above ground and East, Central East, West and Central West are underground. How I roughly remember the exit is like this...
Any has 'West' = Skyscraper side: Keio department store, bus stations to Fuji Mt. and airports, Big Camera & Yodobashi
Any has 'East' = Shopping side: Isetan, OI, LAVI, fast fashion, Kabukicho, 2-Chome
Any has 'South' = Calm side: Shinjuku Gyoen, Takashimaya
THINGS TO DO IN SHINJUKU
1. Shopping all day long
Let's say Shinjuku has everything you can think of - luxury brands, fast fashion stores, Isetan and Lumine, Takashimaya, electronics and etc... You can spend ALL DAY shopping in Shinjuku. Also, great new for those guys whose into fashion. There is a department store called ISETAN MEN'S which has only men's products!
2. CHILL in Shinjuku Gyoen
Shinjuku is known for a busy and crowded city and you will surprise how peaceful it is in Shinjuku Gyoen. It's kind of like the Central Park in New York City. You can have a picnic with your family, or if it's in season you can enjoy cherry blossom and coloring leaves.
3. Bar hopping at Omoide Yokocho
Omoide Yokocho is the secret of Shinjuku bars. Tourists usually go to Golden Gai but it became too much of a tourist spot - they will rip you off. (I got ripped off once even though I'm Japanese.) Omoide Yokocho used to be filled with old 'salary-man' but now it became a trendy thing for young adults. Food and drinks are quite affordable too!
4. Get lost in Kabukicho
Kabukicho is known as one of the biggest red light district in Japan. It's pretty cool to walk around and check out the views but be careful with spams and Yakuza.
Yeah. You gotta see that Robot Restaurant at least once. Well, the entrance fee is ¥8,000 and pay ¥1,000 extra for a cold bento box... I would rather spend my money to go Disneyland instead.
6. Pretend the movie scene at Park Hyatt Bar
7. Explore underground
There is a long underground path in Shinjuku which allows you to shop even on a rainy day. This map below is where you can get to!
8. Fun time at VR Zone
At VR ZONE, you can experience Vertical Reality Games! I believe the best ticket would be 1 day 4 tickets set which means that you can play 4 different games.
9. Fish-n-Eat dinner at Zauo
Zauo is a seafood restaurant where you can fish your own food and have them cook. It's not the cheapest place but it's fun to choose your own food. Also everything is super fresh, so it cannot be bad!
10. Meet Gozilla
Did you know you can meet life-size Gozilla in Shinjuku? Gozilla is in the top floor of Toho Cinemas. They have a little show every hour from 12-6pm so check that out at least once if you are in Kabukicho area.
SHINJUKU LOCAL EATS