I'll add two:

1. Signal when passing another cyclist or pedestrian. A loud "On your left!" is courteous and will help avoiding a crash.

2. Get a mirror and use it.

Also, I know it is not legal, but I ride the sidewalk in sections of roads with lots of fast moving traffic and no bike lanes. The local police have seen me doing it multiple times and have never stopped me. I think it is just safer some times. If I am on the sidewalk, I always travel in the same direction as traffic on that side of the road, slow down, and yield to pedestrians walking on the sidewalk. You have to be really cautious about cars turning in and out of driveways and side streets.