How to walk: Fast. Even if you don't know where you're going, walk quickly until you realize you're going in the wrong direction. Then throw your hands in the air, look accusingly at the people milling around you, and stalk away in the right direction.
Topics of conversation: Be prepared to tell anyone you invite over to your apartment how much you spend in rent. For some reason, rents are exempt from the tackiness of discussing money. Also, comparing subway routes is always good for a round or three of conversation -- but only if you have discovered an impressive new shortcut or have figured out the perfect connection times.
Where to eat: Chipotle is everywhere, and it offers potent $5 margaritas, which means you can get a nice buzz on during your lunch break. Only people in sunglasses who look as if they don't have to work can get away with eating outside; if that's not you, stay indoors. You are allowed to eat exactly one hot dog from a street vendor; after that, you must find a Gray's Papaya.
How to attend the theater: Pick up your tickets during the day. Show up no more than 10 minutes early (all Broadway shows begin at five after). Do not loudly discuss how you've had a crush on such-and-such Hollywood star currently slumming on Broadway before, during, or after the show. Do not voice an opinion in the theater at all; criticisms should be held until you are 15 feet away from the lobby doors.
How to attend the movies: Smuggle in Duane Reade snacks (cinnamon-yogurt-covered pretzels are a good choice) and a thermos of booze. Movie tickets in NYC cost $13; don't spend the same amount just for popcorn.
How to smoke: Hope you left behind some friends in Podunk, Iowa, because you'll need them to mail you cartons of cigarettes. Otherwise, be prepared to cut way back on food to afford your $12 pack of Parliaments. Never bum a cigarette from a stranger, but always take money from strangers bumming a smoke from you. And keep a book of matches in your pocket always.
How to take a cab: Never, ever tell the cabbie where you're going until you're inside. Cab drivers really hate driving the people most in need of a cab, i.e., Brooklynites and citizens of Queens.
When to look up: Only for skywriting or lightning. Otherwise, never.
How to tote: You don't have a car anymore, so you have no place to leave a handy pile of possible necessities. Guys, this means that the time has come to get a man bag. Messenger bags are always in style; backpacks are not. And don't even think about a fanny pack, even "ironically."
How to travel: Memorize the subway map immediately. Learn the regularly scheduled service interruptions. Bonus points if you figure out the bus maps and schedule, but underground is the way to go for the most part. Never, ever engage with subway buskers. A mariachi band is a mariachi band, even underground. And don't even think about applauding those limber guys who make you move so they can do backflips.
When to reference "Sex and the City": Only when decrying the gentrification of NYC, a process that you weren't even aware of because you just arrived in town. But pining for the NYC of yesteryear is the quintessential essence of life here. If people nod sagely when you complain about how the East Village is too clean these days, congratulations. You're officially a New Yorker.