Traffic - as Westtexas said - wear very bright clothing. Yellow is most visible against black streets - be very bright. Hot pink, lime green, bright reds.

Signal all of your intentions. Act like a slow moving vehicle. Ride WITH the traffic, never against it. Think about how you drive. When you come to a stop sign, you look left because that's where the traffic is coming from. More cyclists get hit because the driver isn't expecting anything coming from their right.

In a bike lane, ride closer to the LEFT of the lane rather than hugging the curb. Drivers merging into your lane will see you easier (they often won't crane their necks all the way over to the curb. Also, you stay out of the debri = less flat tires. Any trees or other shrubbery blocking their view of you will be less likely to do so.

Coming up to an intersection where you have the green light or right of way - if I think somebody is going to do something stupid (I can see the driver is texting, eating or otherwise not looking at me), shift into an easier gear where you are pedaling faster and slowly apply the brakes so you can stop if you need to. Drivers think bicycles = slow but if you're pedaling faster, they think you are actually going faster. Be prepared to stop.

Unclip - I always unclip with my left foot. That way, I can't fall into traffic.

I took an Effective Cycling course through my community college that taught me these things & lots of other tips. I recommend it.