Know where your children are at all times. Always lock your car doors. This applies to when you are in your car and when you leave your car. Place them in the car trunk or take them with you. Never hide spare keys in or on your car.
Thieves know of all the hiding places.
If you need spare keys, keep them in your wallet or purse. Park as close to entrances or active areas as possible. Avoid parking where you see someone sitting in their vehicle for no apparent reason. Try to park in well lit areas as close to the mall entrance as possible.