Michael Bluejay has a lot more to say about this. You can read about him at this link. And to read more about his advice, read below and then link to his Bicycle Safety web site.
From Michael Bluejay:
This is a far cry from normal bicycle safety guides, which usually tell you little more than to wear your helmet and to follow the law. But consider this for a moment: Wearing a helmet will do absolutely nothing to prevent you from getting hit by a car. Sure, helmets might help you if you get hit, but your #1 goal should be to avoid getting hit in the first place. Plenty of cyclists are killed by cars even though they were wearing helmets. Ironically, if they had ridden without helmets, yet followed the guidelines listed below, they might still be alive today. Don't fall for the myth that wearing a helmet is the first and last word in biking safety. In truth, an ounce of prevention is worth a pound of cure. It's better to not get hit. That's what real bicycle safety is about.