One mistake that some people make is they talk to the other driver's insurance company and give a statement. Now a lot of people say, "Well, what's wrong with giving a statement, I'm going to tell the truth about what happened, so why should I care?" The reason you should care is because the insurance adjuster taking your statement is trained to get you to say something that is going to help the insurance company and not help you. For example, if you were rear ended, they may ask you, "Before our driver hit you in the rear, how far away were they before you slammed on your brakes? And then you're going to say they were three car lengths behind you when I saw them. And you're not going to pick up on the fact that they're getting you to almost admit that you slammed in your brakes.
I'm not saying that every insurance adjuster is going to try and trick you into admitting something that's true, but some of them will. Be very, very careful about giving statements. You do not, you do not have to give a statement to the other person's insurance company. You shouldn't. Anything you say can and will be used against you later.