NYC is fab!
you will walk miles so comfy shoes.
have a look at the map and group things together according to area.
The high line is lovely and Chelsea market for an on the go dinner/lunch.
look into buying theatre tickets before you go, we queued up in Times Square - 2 hrs in the rain and most of the top shows had sold out - we saw a new to broadway show called Kimberley Akimbo - it was really good though.
See if there’s any sporting events while you’re there - we watched a basketball match in madison square, now I’m bit a basketball fan by any means but it was so entertaining- was a highlight of our trip!
The original Winnie the Pooh is in a glass cabinet in the New York library, worth a look if you’re passing.
Empire state building is one of my favourite places ever - it’s iconic - so many movies filmed there you feel like you’ve been there before. Plus great views!!
Transport wise, we found the subway ok. It was busy so not scary but not sure I’d use it alone at night.
Walk Brooklyn bridge - pizza in Juliana’s is one of the nicest pizzas I’ve ever had.
Bubba gumps restaurant in Times Square was good for a meal too - staff were really entertaining and the food was lovely! Not as expensive as I thought it would be.