The blind spot of a driver is a vulnerable position for a bike rider.
Position yourself on the road where drivers are most likely to see you. Remember that larger vehicles have larger blind spots.
Try to establish eye contact with motorists. It will let you know if they have seen you or not. Never assume you have been seen.
Ride defensively. Ride carefully when positioned next to a car as this is a vulnerable spot. The car might turn left into a side street without checking for riders. Slow down and make space so you are seen in car mirrors.
Learn to anticipate driver actions and watch for cars that are indicating or slowing down as they approach a junction.