1. Make sure you are safe.
The number one priority is always the physical safety of everyone involved in the accident. You'll want to contact the police and get immediate help for anyone who is injured.
2. Remain at the scene of the accident and exchange information with the other driver(s).
In Arizona, you can be charged with a criminal violation if you fail to remain at the scene of the accident (a.k.a. hit and run) or if you fail to exchange information with the other driver. You must do these things even if you were not at fault for the accident. Collect the other driver's name, address, phone number. Get the other driver's insurance information. The other driver is required to provide ID if you ask for it, and is required to provide insurance information. Get the names and contact information of any witnesses or vehicle passengers too.
3. Preserve evidence.
If you are able to safely do so, take as many pictures of the accident as you can. As soon as the tow trucks arrive and start moving vehicles, you are going to start losing evidence. Take pictures of the damage to the cars, license plates, the people involved in the accident and the locations of the cars including street signs. We have seen situations where the cops didn't take a single picture of the accident scene.
4. Seek medical help.
A traffic accident is a high-adrenaline event. Immediately after an accident, you may not realize you are injured. Internal injuries like head injuries or bleeding may not be immediately apparent. Do not refuse treatment on the scene. If the paramedics decide not to transport you to the hospital, go see your primary care physician or go to the emergency room. Failing to seek prompt medical attention can weaken any subsequent injury claim you might make.
5. Call your insurance company.
Some insurance policies have requirements about contacting your carrier in the event of an accident. If you fail to contact your insurance company, they might deny you coverage. If you think your insurance company might decline to cover the accident, you should skip to #6, and call an attorney first. If you are contacted by the other driver's insurance company, politely decline to answer any questions or make any statements until you have your attorney with you. Then go talk to an attorney.
6. Talk to an attorney.
Call an attorney early. An attorney can help make sure you do not make any mistakes that might ultimately reduce your recovery. If you engage an attorney, that attorney can engage with the insurance companies on your behalf while you focus on your recovery. Any good personal injury attorney will discuss your case with you at not cost to you.