It may be safer to take the whole lane in narrow lanes or slow traffic. Signal your intentions in advance. Move to the left turning lane, and complete the turn when it is safe. Signal all turns and stops ahead of time. Look over your shoulder for any traffic, then make your intended move only when it is safe to do so.
Motorists can unexpectedly open doors.
Be particularly careful if you see a motorist in the car. 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.