1. Stay calm, it will help you to resolve your situation properly. 
2. Check the well-being of your passengers and verify that all occupants are safe.
3. If possible, find a safe place to park.
4. Call 911 and/or the police department.
5. Don't be reckless when exiting the vehicle and wait for help. 
6. Do not assume responsibility and exchange information with other drivers. 
7. Not all people act in good faith, ask for proof of insurance and/or driver's license.
8. Obtain evidence of what happened. Preferably take photos and videos that show how the accident happened. 
9. Notify your insurer and initiate the claims process.