If you see a Tibetan monk who speaks no english and he asks you to hold his coin, dont. He'll expect you to pay him for holding it.
Yes, this is a real tip brought to you by a real life experience.
Other than that I'd make a plan of what you want to see/accomplish and try to stick to it. It's so easy to lose hours in NYC. I've stayed in Queens the times I wasn't staying with friends, you can find decent priced hotels there.
Shows are fun too, like
@BuegeSmalls said! Matilda is usually decently priced and it's closing day was just announced so it's days are numbered (see it while you still can!). Plus it's a musical without being too musical-ly.
Make sure you bring one of those phone charger packs that can charge a phone atleast twice. You'll probably be using your phone to navigate, check train times, take pictures, etc and your phone will probably die multiple times.