Unlock power door locks -- in case electricity quits.
Turn the ignition OFF -- to shut off fuel pump and spark plugs.
Pull the hood release -- so firefighters can put out fire.
Get everyone out of the car.
Call the fire department.
Leave the sunroof, windows and doors closed.
Don't open the hood -- starve the fire of oxygen.
Don't fight the fire yourself. Water won't put out gasoline or electrical fires. Only TYPE B and TYPE C fire extinguisher. Dry chemical is most effective, but leaves corrosive residue.
If the fire is under the car: Get out and stay away. The gas tank could explode.