Simply, never argue at the scene. Let the evidence do the talking. Call the police immediately and insist on the report, even if it’s a minor accident.
Take photos of everything from vehicle positions, skid marks, traffic signs, road conditions, and all the vehicle damage from multiple angles.
Get witness contact info, not just the names, but their phone numbers and emails. Don’t rely on the police to do all of this for you.
Write down your version of the events as soon as possible while your memory is fresh.
Seek medical attention immediately, even if you feel fine. Adrenaline can often mask your injuries.
And most importantly, don’t give a recorded statement to the insurance without an attorney. Their position doesn’t determine the outcome. The evidence does.