I stumbled upon this short but totally on-point guide on how to not be a douchebag while visiting New York City. Honestly, if you are planning a trip to NYC, I couldn't recommend this guide enough. It covers topics such as transportation, tipping, dealing with homeless people, etc. The 'rules' mentioned in the guide are nothing special - you might as well call it common sense.
How To Not Be A Douchebag Tourist In NYC [CO-ED]