First of all, watch this 11 minute video tutorial. It is by far the best video I've seen on how to ride in traffic and why it's essential to ride like any motorcycle or motor vehicle. It will seem counter-intuitive but these tactics work and will minimize risks.

Wear a helmet. Put lights on the helmet. You need two or more points of light to enhance visibility. The human eye can better tell at a glance the direction, speed and orientation of another moving object when it has two or more converging or diverging points of light. That's why cars are easier to see at night even when it's too dark to see anything but the lights. That's why some larger motorcycles are easier to see. Two or more points of light, separated by at least 12 inches and preferably more, make us much easier to see.

Here's what I've worn on my helmet for almost three years:
This headlight.
This taillight. The Blackburn 2'fer is a multi-mode light with built-in white and red, steady and flashing. A pair can be used as front and rear lights.

They weigh almost nothing and are very compact. They'll mount easily to most road bike type helmets -- the types with lots of vents. It's trickier to mount lights to helmets with fewer vents -- those trendy but impractical Bern and skater type helmets. Incidentally, those more solid helmets are somewhat deceptive. It seems like they should be safer. In tests, they aren't. The road bike helmets with lots of vents are lighter, more comfortable and test better in impact tests. And you're more likely to wear them because they're comfortable in hot, sweaty summer weather.

Both lights run about the same length of time, recharge about the same, and are durable. I've used them on almost every ride for nearly three years.

I run them on flashing mode. I can see that they work because I can see that drivers see me. Many times I've seen oblivious drivers nearly pull in front of me, glance my direction and slam on their brakes before pulling out in front of me. When I run the front light on steady white drivers tend not to notice me as readily, about the same as riding without a helmet light at all.

The only time the lights didn't help was last month when an oblivious driver, distracted by a cell phone and turning left into my path, clobbered me. It was still light out, the low late afternoon sun was behind me, and it would have taken a much brighter light, a loud horn and Pennywise the clown from It to get that driver's attention.

But I'm satisfied that running multiple lights has reduced my risk overall. Along with cycling as the above video demonstrates.