If someone tailgates you, first wait a bit before looking back. Maybe he accidently gave it too much accelerator. But if you check your mirrors when you can do so safely in a minute or so and he's still there, then slow down even more, little by little, so as not to try to make the guy behind you go ballistic. That will give you more time to slow down and stop if something jumps out in front of your car, in turn giving the tailgater more time to slow down and stop and not smash into you. It also gives the tailgater a better incentive to pass you, especially if you slow down in an area that's safe to pass. Ya, he'll probably get mad, honk his horn and make gestures with his fingers. But at least you'll be safer.
If someone pulls out right in front of you ease back off of him as safely as you can. If you can, tap your brake pedal lightly a few times so the guy behinds you knows you're slowing down. Sometimes you do have to brake hard to keep from smashing into the next car, but that will turn on your brake lights anyway.
There isn't much you can do about people driving extremely fast except getting a safer car and perhaps a better insurance policy (or just be ready to sue the tar out of the sucker who slams into you if you're still conscious). Newer cars are safer, and SUV's do better in accidents. However, a full sized sedan is very safe and easier to maneuver out of a potential accident.
And overall, don't pay too much attention to the other drivers. Just drive as best as you can and let them act like idiots. My only ticket I got was because this guy was right on my bumper and I kept looking in the mirror. Next thing I know a police officer pulls out behind us and I thought he was going to pull over the guy behind me. But no, I apparently was going 9 miles over the speed limit and got a $160 ticket, which I was struggling financially at the time and that was all I had for food that whole month! Since then, that has been my first and last ticket. The morral of the story is to keep your focus on what you're doing, not what everyone else is doing.
Some day you'll get to enjoy a snow storm and watch SUV's and pickups go off the road left and right while you keep right on going, perhaps in a little 2WD car.