After getting hit several months ago while riding my brand new Surly Long Haul Trucker, I've been riding much more defensively ... !!! I have slowed down a bit, sometimes quite a bit!
I always assume the worst -- Meaning that I assume the drivers don't see me, are not going to stop or slow down for me. The drivers are not going to yield the right of way for me. The drivers are going to swerve into the lane where I'm riding (including the bicycle lane, or the shoulder/gutter), and crash into me.
I've decided that my life is too valuable to take any chances. So, if there are any motor vehicles close enough (without a block or so), I wait until the vehicles are gone. If there are any vehicles, I stop at the stop sign. I always stop at signal lights.
I've found many alternate routes to avoid some of the busy streets. I watch my rear view mirror (large HubBub hex mirror!) very closely, and slow down, and stay as far right as possible, to allow the traffic to pass me, then ride in the lane again, unless I don't need to.
I've decided that at least some places, it is much safer for me ride the sidewalks! So, I ride on the sidewalks in places where it is just too dangerous to ride in the street.
I have three taillights flashing both day and night. Headlamp and flashing SuperFlash in the front (day), and headlamp and helmet lamp at night.
I keep my eyes on the road, and pay very close attention to what is going on, where cars might pull out of a driveway, alley, etc.
Oh yes, and I always where my helmet ... !!! Even in the triple-digit weather.