Oooo I went for the first time this year and totally fell in love with the place! We have friends who live there so got lots of tips..
Don't do top of Empire State.. instead book a table at 5pm at the rainbow rooms bar at Rockefeller... enjoy cocktails and food while watching sunset over the city.. amazing views which includes view of the Empire State lighting up. I emailed and booked a table a couple of months before I went, they reserved me a table right next to the window... it was fabulous!
Walk the highline... it's free.. a disused railway up high between the buildings that's been turned into a park. We went to Chelsea market first for a potter round and lunch (it's a really nice food market.. think borough market London) the highline starts really near to there. Highline is less than 2 miles long so a nice afternoon walk.
Get to the Staten Island ferry to see Statue of Liberty... it's free (don't be conned by a tout flogging paid for boat trips outside of the terminal) when you get on, go to the right side , race to the end of the boat, go down stairs and grab a window seat for the best view!
Definitely do 911 museum. There's. Massive queue.... but on the other side of the building from the queues there are 3 ticket machines in the wall which look like ATM machines.. very short queues for those! Not sure why but people don't seem to realise they are there! You book a time slot on the machine for your entry to the museum... get the ticket and while you wait for your time slot you can get your hotdog from a street vendor! 😁
Def do a west end show.. we did Book of Mormon which was hilarious but if you are easily offended by literally any subject then it might not be for you! Short walk away Just off Times Square is Gallaghers steakhouse... OMG the best steak I've ever had in my life! And real old school classic New York.. highly recommend!
We like just wandering round the streets in Chelsea/Greenwich.. gorgeous buildings, nice but not overly expensive bars...
Hire bikes to ride round Central Park... it's massive!!
It's amazing! Enjoy!