Treat all cars as if they are trying to kill you. They are.

Use turn signals. Make eye contact when you are signaling a driver of a particular car. Don't be wimpy with your signals, be assertive, don't be afraid of directing traffic.

Speed is your friend. At 7 to 10 mph you are a sitting duck. At 20 mph you are a darting rabbit. The faster you ride, the more time cars behind you have to see you.

Keep track of right of way and yield when it is not yours. Always stop at traffic lights, but I find it is safer to blow through a stop sign before any cars get to it than do a legal stop and then have to play who has the right away once the cars also come to a stop. Also, I will run traffic lights if I don't have the weight to trigger a left turn signal and I am in the left turn lane. Assuming it is safe of course and there is no car around to trigger it for me.

In really busy intersections, don't be afraid to get off your bike and walk it across the street. As a pedestrian you trump all other right of ways.

When a fast road bike passes you, draft him. You will get across town much faster.