Summarize:

If your cars are still operating in traffic, signal remorse by waving or mouthing "I'm sorry." It is possible that you did nothing wrong, but your priority should be to deescalate the situation rather than sort out blame accurately. Apologize. If you are stopped and the driver approaches you, acknowledge you were wrong. Do this even if their anger is disproportionate, or if you do not think you were wrong. This is hard to do, but letting them "win" could quickly bring further problems to a short end. Your main goal should be to stay safe, rather than to win an argument. Avoid inflammatory statements, and allow the driver to feel like they have gotten what they wanted. Give up a parking space even if you were there first, let the other driver merge into your lane even if it isn't their turn, give more breathing room between your cars, or leave the fast lane even if you are driving at the correct speed. Ignore insults. The enraged driver may insult you. Remember that they are angry and that their insults do not truly apply to you. Do not reciprocate when insulted. Calmly but assertively state that a neutral authority should resolve the conflict. In some cases, you may be just as angry as the other driver. Before you engage in direct confrontation, take basic steps to calm your own nerves. Breathe deeply, counting each time you inhale to ten. Remind yourself of who you are beyond the stressful moment. Think about how your family, friends, or coworkers expect you to act. Think about something that you are looking forward to. Look past the unpleasant moment and remember that it will be over soon. After the incident, when you've calmed down, reexamine the events that took place. Determine if you did anything wrong or if a specific action may have helped cause the other driver's anger. Now that you are safe, it doesn't matter who was at fault. Simply determine if there is something that you can do differently next time to avoid triggering other motorist's rage.
Show remorse. Let the other driver win. Calm yourself. Analyze your driving.