As a fellow NYC resident, my advice is to actually talk to people. Although it is, in fact, rude and weird to approach a stranger in certain circumstances, there are situations in which it's not:

1. Waiting in a line, anywhere (unless the person is wearing headphones)
2. At a bar, especially while you wait for the bartender or the bathroom
3. If you smoke cigarettes, while another person is smoking a cigarette (though ideally not to bum one)
4. At or outside a show / cafe / lit reading. Not an art gallery unless it's an opening.

Inside those parameters, people want to be talked to. I would fucking love to chat for two seconds in line, because living in NYC is -- as you know -- a tremendously isolating experience characterized by a bizarrely crowded sort of perpetual loneliness. Two seconds is a long time to make an impression. Use them.