A few years ago I moved from LA, where I used to ride on the glorious fire roads in the Los Angeles National Forest (above Altadena), to NYC, commuting and doing errands in Brooklyn, Manhattan and Staten Island. So instantly I hated everything about it. But I learned to adjust, so here's a list, FWIW, of stuff I learned.
1. Avoid the Brooklyn Bridge and use the Manhattan Bridge. Things are better on the BB if you use a bike bell (sometimes it works wonders), but you just can't change the behavior of every tourist who walks on that bridge. And do I really blame them? The views are glorious. Too bad that when you're biking, you can hardly peek at all.
2. Carry at least 2 spare tubes. The other day, I got stranded on the Shore Parkway Greenway, SW of Bensonhurst (about a half mile N of the Toys Are Not Us) because the valve stem on the crummy Nashbar tube I bought broke. (Avoid those-- they're threaded all the way down, so the loss of material makes them weak.) Then I got stranded halfway across the Manhattan Bridge because the patch that I had applied just before I got on the bridge didn't hold. Maybe the tube was dirty or it was too hot for the glue (one of those 90 plus days), but there I was, without any tubes (because I had used the last one in the incident I just mentioned.) A lack of planning is a great teacher, if you can learn the lesson.
Related to this, I guess no NYC biker will stop when you're stranded and ask you if you need help. In LA, at least on hilly roads outside the main grids, if I was on the side of the road pumping up a tire, occasionally people would stop and ask if I needed a lift or a tube. Not in NYC. Maybe you have to flag them down and beg.
3. This isn't a solid rule, and practically no NYC bikers follow it, but recently I've been trying to stop at more red lights. It's part of my (probably grossly mistaken) belief that if drivers see you respect the rules, they'll respect you more. Sounds naive now that I wrote it!
4. Avoid riding to the right of cars and trucks in tight intersections. It's just a recipe for getting nailed if they make a right turn. A lot of cars don't use their signals, so you don't know what they're going to do.
5. The Hudson River bike-way (on the West side) has pretty nice bike lines, but the one on the east side, running from the Lower East side to around 34th St. has no markings for bikes vs. peds. It's basically a street that was converted. (Maybe somebody can give some history here.) It's been patched a lot (very uneven), though there's no glass. There are also parts that are extremely tight-- really just walkways wide enough for one bike and one person. It's probably faster to get to mid-town (and safer) than riding one of the avenues, but it still leaves a lot to be desired.
6. You can't change the behavior of all the delivery guys in Man. and Brooklyn who ride the wrong way on one-way streets and bike paths. If they get killed, I guess it's their own damn fault.
7. You've got to chain and lock everything down. It's a drag. I used to just take off my front wheel and lock that, the rear wheel, and the frame with an Abus U-lock. But then I started to freak that someone would steal my components. Maybe it's paranoia, but there just weren't good places to leave a bike outside in Mid-Manhattan for 8 hours straight. Anyone ever seen the so-called "Bike Shelter" (really a converted covered bus stop) outside of Penn Station/Madison Square Garden? I guess the engineers didn't think that walls were necessary to protect bikes from rain and snow. Anyway, that area (theoretically) is watched by a big camera, so maybe that provides some insurance if park a bike there. On the other hand, probably you could never find the thief anyway, and probably the cops don't care.
My recent solution was to try to find an under-the-radar bike to use as a commuter, one that I could keep tuned but wouldn't look like much. I haven't found the magic formula bike yet. Right now I'm using a friend's old Nishiki. For security, I'm using the Abus U-lock, a cable for the front wheel, plus a chain and a padlock for the seat (because it has a nice special cut out seat to protect your soft parts.) Yeah, the heavy chain and Master padlock for the seat are probably overkill, but after somebody stole a seat clamp (I had removed a quick-release seat from a mountain bike I was riding temporarily, but forgot the clamp, so it vanished), I realized that people will steal anything here.
8. Avoid riding in Prospect Park after 3:30 pm and afternoons on weekends and holidays. It's just no fun, even with the new expanded bike lines. There are still joggers who want to run in the x'ed-out dead zone between the bike lane and the pedestrian lane (even though every mode of transport now has an ENTIRE car-width lane), the nannies with their strollers, and bicyclists who still ride the wrong way. I'm not a big fan of the racing types, either.
9. Don't buy a seat post rack (the type that either clamps or bolts to the seat post and has no supports to the seat stays or the chain stays.) It sways/rotates under loaded panniers. It will go into your rim/tire, causing you to have to stop and try to tighten it down. Then you will more than likely strip the aluminum bolts (at least on the Delta model I have) and want to throw the whole thing away, where hopefully it can be melted down and reformed into something useful. I plan to get a better rack (probably a Racktime and use some special brackets that can fit on a bike with new eyelets. The Radonnee shop sells them.) But right now, I have a very odd rig consisting of the Delta seat post rack supported by some PVC tubes, connected to the chain stays with electrical C-clamps. It stabilizes it, a little.
My conclusion: With the rise of bike lanes, signs, and general bike culture, riding in NYC is many magnitudes better than it was 10 years ago. Most of my adaptations have less to do with the infrastructure than with the conditions (road debris and glass, leading to flats) and human behavior (drivers and peds). You can deal with conditions through preparation, precautions, and better equipment (extra tubes, carry tools, better tires) and deal with human behavior through defensive riding and being self-reliant. But I still don't find the whole thing very enjoyable. It's just been hard to adjust, even when you're riding west on 34th St. and get a great view of the Empire State Building, or ride along the water on one of the bike-ways.
Maybe fellow riders can cheer me up a little bit.