Two parts. One from a state ordered defensive driving class, the other from other places.
Go with the odds. Most accidents happen at intersections, so slow down and be careful there. As VCO3 said, assume the other guy isn’t paying attention. You may have the right of way, but not crashing is more important than being right.
Oddly, very few accidents happen head-on, against the person in the other direction. Far more happen from cars or pedestrians leaping out from the side of the road. So, hug the center line, not the side.
Aside from brake lights, other signs indicate that another car is slowing. A car ahead of you emits a lazy puff of exhaust? He’s gotten off the gas, and he’s slowing down. A car coming toward you dips down in front? He has hit the brakes. He might turn into your path.
If you approach a car that’s weaving in his lane, or has had the turn signal on for the last half mile, the driver is not paying attention or is impaired. Don’t get close. He’ll have his accident, and you needn’t be part of it.
On a two lane road, you need a half mile between you and approaching cars for you to make a pass. If you can detect motion in the approaching car, it’s less than a half mile.
It is better to go slower than you want than to make a foolish pass. The difference might be your life.
Now, the other part:
If you are passing a big truck, and he flashes his brights at you, it means it’s safe to change lanes back in front of him. The “thank you,” if you want to do it, is to quickly shut your lights off, then turn them back on.
Your turn signal alerts other drivers you’re about to turn or change lanes. Allow a little time for the other driver to see it. Again, assume he’s changing stations on his radio or looking at hot babes on the sidewalk, so give an extra second or two.
Your cruise-control does not entitle you to tailgate. Disengage if you get too close.
At night, if you have to stop for gas of coffee, put on your sunglasses to enter the bright lights. The chemical (visual purple) that lets you see at night can be bleached out by bright light. It is better to look weird mormentarily than to be night-blind for the next few miles.