Always look inside before entering your car.
Park in well lit areas at night.
Lock all doors immediately after you are in the car.
Never pick up hitchhikers.
If a stranger approaches while you are in the car, keep the windows up, doors locked and engine running.
Honk your horn if you need to attract attention.
Always lock your car when leaving it.
Consider installing an auto burglar alarm system.
Don't leave anything valuable in your car if at all possible.