It is important that you remain calm, particularly, if others in your family are injured or required help. Call 911 if necessary or ask someone at the scene to call for medical attention.
Call the police
When someone is seriously injured you should wait for the police before moving the vehicles, if possible.
Cell phone photos of the vehicles, their positions on the roadway and the property damage can be very helpful when presenting an injury claim.
Follow all instructions of the hospital and your treating doctors
Many times victims of car accidents try to "tough out" the recovery process in the hopes of avoiding the costs or inconvenience of treatment- get the treatment / help your medical providers suggest. Lapses in treatment can be pounced on by the insurance company in an attempt to minimize your injury.
Do not give a recorded statement to the adverse insurance company before you talk with an experienced attorney.
Adjusters have been trained how to inquire into topics designed to aid in the defense of the claim and to reduce any injury claim. Speak with the lawyer of your choosing before you give such a statement.
If you require help of an attorney, find the best one you can
Generally most attorneys who handle injury cases do so on a percentage basis- the more money you receive the more they get paid. Research the attorneys, their peer reviews and past record of success and go with the best you can find.