I LOVE NY
I long to live there one day.
Only good advice I have is on Shopping and Food, and I am guessing Shopping is not high on your priority list, Ill stick to the second best thing about NYC
The food is awesome, it maybe a bit of a cliche but you have to head to Grays Papaya on 72nd and Broady, the best hotdogs ever and super cheap, also try the coconut fruit drink its yum. I think there is another GP on 6th aswell.
A cupcake or two is needed from Magnolia's on Bleeker st, Oyster Bar in Grand Central is lush and scrummy, La Esquina on Kenmare st has the best cheap Mexican with awesome tequilla and lots of it. Shake shack in Madison Park has the best cheese burgers ever.
There is plenty more but I think I covered most of my favs.
Hope you have a great time in NYC