1) Do not, under any circumstances, keep your wallet anywhere but in
your front pockets.
2) Do not, under any circumstances, make eye contact with anyone
unless you either a) know them; b) are buying something from them; c) trying to get laid.
Sunglasses help in this regard.
3) Despite what they say, concession stand vendors selling Ground
Zero, NYPD, NYFD, or generic 9/11 souveniers are not giving one dime
to any charity.
4) Ditto for those homeless guys with water cooler jugs on the street.
5) Do not buy street nuts.
6) Do not buy street dogs.
7) If you're in or near Times Square, congratulations, you just paid
too much for breakfast/lunch/dinner.
8) Do NOT attempt to buy anything from those generic electronics
stores unless you are a veteran haggler.
9) There was a great NY Times piece on how most of the people you find at Ground Zero are just morbid tourists, and I tend to agree. You can pay respect without actually going there.
10) South Street Seaport is cool, go there.
11) You get to stay at the top of the Statue of Liberty for less than
a minute, it's only worth the hike if you're reasonably sure you'll
never, ever be in New York again.
12) Don't look up at the skyscrapers.
12a) Don't look at any map while out on the street.
13) You can window shop at Multimedia 1.0 on St. Marks, but for the love of all that's good and pure, don't buy anything. They gouge, badly.
13a) On the upside, despite the apparent commercialization, St. Marks is still the best place to find a great selection of used movies and music, plus other random crap.
14) "Riese" is code for "Likely infested with something unholy."
15) If you see a celebrity on the street, keep walking. They like New
York because people are kind enough to ignore them.
16) Get a weekly Metrocard.
17) For a great turkey burger, All American Burger on 32nd and 6th
(ish); for a slightly burnt (but still good) ostrich burger, Better
Burger on 8th and 19th.
18) Just say no...to fanny packs.
19) If you need a good place to just chill out, any one of the giant
rocks in Central Park will do just fine.
20) 19 is probably not a great idea in cold weather.
21) Walking around at night is fine, just use common sense.
22) Marveling at the size of the rats on the subway tracks is ok; it
even amazes us natives.
23) Speaking of the subway, if you get on a train going in the wrong direction, don't panic. Calmly get off at the next stop, and follow the signs to the trains going in the opposite direction. You won't need to swipe your MetroCard again.
24) There's more to New York than just Manhattan. You'll find penty to do in the outer buroughs as well.