New York Magazine has published a great multi-page guide to being polite in the big city. Contributors cover everything from "How not to alienate That Guy From TV" (tips for brushes with celebrity) to the fine art of walking behind a woman into an apartment building in a way that tells her you're not a mugger or rapist (don't immediately follow her into an elevator or stairwell, and if necessary, use a feigned cell phone call for a stalling maneuver). There are also helpful (and humorous) diagrams to aid your study. Some of the tips are more NYC-specific than others, but most are good manners in any city, and many are just good manners in general.
Found via Lifehacker.