There's more to auto safety than being a good driver. Keeping your doors locked and windows rolled up, parking in well lighted areas, and looking inside your car before entering are all safe practices.
Tips
If you feel you're being followed, do not go directly home. Instead, drive to the nearest police station, hospital, or other public area.
If your vehicle breaks down, pull onto the side of the road, turn on your flashers, open your hood, and tie a piece of material to the antenna. Get back in your vehicle, lock the doors, roll up windows, and turn the engine off. When someone stops, roll down your window enough to talk and ask them to call for assistance.
If you have a cell phone or CB radio, use it to call for assistance.
Be very careful about your keys. Only leave the ignition key with parking or service station attendants. That way you won't run the risk that other keys will be duplicated.