Riding in NYC Safely

For starters: Stay alert, be respectful of everyone, and keep your speed in check. This will form the foundation of safe riding.

1.) Remember that you're invisible to some
When you drive in a car, you can usually assume that other drivers will see you in their rear view mirror. This is not the case on a bicycle! Assume that you are ALWAYS in a car's blind spot, and that a driver can ONLY see you if you are in front of them. Do not expect driver's to see you in their mirrors. 

Pedestrians can and totally will jump out in front of you at any moment. This is NYC.
Always have front and rear lights for night riding. Reflectors on your pedals are also important as the constant movement is eye catching. Wearing bright colors during the day can also help being seen. Don't be afraid to use hand signals to let people know where you're going.

2.) The road will change. So will your bike! Stay alert.
Be mindful of two major factors that cause accidents: the road and your bike. Tires can lose traction sometimes! Keep an eye out for anything on the road that will cause your tires to slip (bumps, grooves, oil, debris, ice). Scan far down the road and always look where you are going; look through your turns. If you ride in the winter, be very cautious of ice.
A tire blowout can be disastrous when going downhill or in the middle of traffic. Inspect your bike regularly for potential flaws and be proactive about preventative maintenance. Puncture resistant tires are an excellent investment, they will quickly pay for themselves if you ride 20 miles a week.

Riding with headphones will reduce your ability to hear traffic as well as any strange and potentially hazardous noises coming from your bike. Yeah, we know it's fun but, like, at least don't do it at night.

3.) Accidents are almost always the result of multiple factors, try to eliminate as many as you can.
Just like airplane crashes, bicycle accidents are rarely caused by just one factor.
If you've had a close call, realize that even the smallest additional problem could have meant a serious accident (sun in a driver's eyes, minor flaw on the road surface).

Some factors are outside your control, but you don't need to add any to the mix.
You can learn a lot from any accident, and close calls too. A close call is not a good sign about your riding.

4.) Avoid thinking you are not at fault.
You might be tempted to say "I see this pedestrian, but he's in the bike path, so if I hit him it will be his fault." A better response to uncertain traffic conditions is to simply slow down.

5.) Dial it back a notch.
When commuting on any vehicle you place yourself somewhere on the spectrum of slow and safe to fast and danger.  Don't get yourself killed just because you were five minutes late and rushing. Don't get in the habit of becoming angry when people cut you off or drive stupidly or dangerously. Being respectful to others is more important than saving 30 seconds on a commute. Unfortunately, in New York this has never really been the prevailing attitude.

6.) Know your bike and practice crash avoidance techniques.
You should know your bike well; you don't want to learn how to shift for the first time in the middle of traffic.
Practice braking as sharply as you can, this is what you're going to do in an emergency to avoid a crash. Learn how much to apply the left vs. the right brake. Get an idea of how many feet it takes to stop at certain speeds, and practice lowering the distance. Don't try this while turning, only brake sharply when the bike is straight upright. The front brake provides about 70% of the stopping power, so don't be afraid to use it. The rear wheel should skid only a little or not at all. You will need to use your arms to push your body back, as if you are running full speed into a wall. Be aware that the distance will be greater going downhill, in the rain or in freezing cold weather.

If your bike has steel (chrome) wheels you will need much, MUCH more stopping distance in the rain!!