Ride a car's door width away. Establish eye contact with motorists to insure that they know you are on the roadway. Look over your shoulder regularly or use a mirror to monitor traffic. Although bicycles have equal right to the road, be prepared to maneuver for safety. Buy the best lock system you can afford.
None is as expensive as a new bike.
Lock the frame and rear wheel to a fixed object. If you have a quick release, lock the front wheel also. Always use a strong white headlight and a red taillight at night or when visibility is poor. Use bike reflectors, reflective clothing and a bell.