The above link is a set of cartoons giving tips and explaining etiquette in NYC. Some of them are pretty good. A few of them apply to any crowded city. The slow walkers that walk side by side are my personal pet peeve.
I remember going to a conference with my family in NYC when I was younger and someone teaching me how to walk in the city so that no one would bother you. Basically you walk like you have somewhere to be staring directly ahead. I’ve used it in tourist spots throughout the world where panhandlers and street artists try to get your attention every step and they rarely bother me.
I love living in the South. However, when I have somewhere I need to be on time, I sometimes miss the no bullshit of the North East.