Always keep the doors locked and windows up, even when the car is parked in your driveway or in front of your home. (This is also a good idea when you are in the car and driving around.)
Be aware of your surroundings and trust your instincts. Look around before you exit the safety of your vehicle as well as looking into and under your vehicle before getting into it. If it doesn't feel or look right, get away and report it!
Carry insurance and registration cards with you. Do not leave them in the vehicle. Don't leave any personal documents (credit cards, check books or mail) with your name and address on them.
If you leave your car in a parking garage/lot or take it in for repairs, leave only the ignition key with the attendant or repairman. Be sure that no personal information is attached to it (i.e.: nametag with address on key chain.)
Know the make, model year and color of your vehicle. Keep a copy of your VIN (Vehicle Identification Number) and vehicle's license plate number in your wallet or purse, so if your vehicle is stolen you can accurately report the car information promptly.
Never leave valuables in plain view, even in a locked car. Lock them in the trunk or at least store them out of sight if you must leave them in the car.
Never leave your car running or with the keys in the ignition when you are away from it, even if you are planning to "be back in a minute." Why give the thief an easy target?
Park in well lit (under a street light or in direct glare of porch/garage lights) and busy areas. Don't give the thief an opportunity to use darkness as a cover for their crimes.
Report all suspicious or unusual persons, cars or activities to police immediately!
If your car is stolen, report it immediately by calling 9-1-1. The sooner the police know it is missing the better the chances of locating it. Additionally, if you notice abandoned vehicles in your neighborhood, report them as well. They could be someone's stolen vehicle that the thief has abandoned.