The common sense approach is the simplest and most cost-effective way to thwart thieves. Some of these suggestions are obvious; some might not have occured to you. But they can all help protect your car:

• lock your car - half of all vehicles stolen are left unlocked
• take your keys - nearly 20% of all vehicles stolen have keys in them
• park in well-lighted areas - car thefts occur at night more than half the time
• park in attended lots - car thieves don't like witnesses
• don't leave your car running, even for a minute - convenience stores, gas stations, and ATMs
  are common hunting grounds for thieves, and cars left running to warm up on cold mornings
  are easy prey
• completely close your car windows
• don't leave valuables in plain view
• don't hide a spare set of keys in the car the pros know where to look
• keep your registration card with you not in the glove compartment
• park with your wheels turned toward the curb
• if your vehicle has rear-wheel drive, back into your driveway; rear wheels lock on rear-wheel drive vehicles, making them tough to tow; front-wheel drive vehicles should be parked front end first
• always use your emergency brake when parking
• if you have a garage, use it - and when you do, lock both the vehicle and the garage door
• if your vehicle is going to be unattended for a long period of time, disable it-for example, remove the ignition fuse, coil wire or distributor rotor