Park your SUV in a populated, well-lit area. Look for parking lots with security-camera systems or a security guard.
Install an ignition kill switch or fuel kill switch on your SUV. These simple and inexpensive switches are basically hidden on/off switches for your fuel line and ignition systems that prevent thieves from starting your vehicle.
Take the keys with you whenever you leave the vehicle. Never leave the keys in the vehicle. SUV thieves are always on the lookout for unlocked vehicles with the keys in them.
Roll your windows up every time you leave your car. If you have pets that need ventilation, either bring them with you or crack the windows as little as possible to prevent thieves from reaching in.
Find and record your vehicle identification number (VIN). It is usually located on your dashboard near the windshield on the driver's side, but sometimes can be found near the latching mechanism of the driver's-side door.
Use and lock your garage. Your SUV will not draw the attention of thieves if they can not see it, and a locked garage provides an additional layer of security.
Buy an electronic engine immobilizer. This locks your engine when your key (which has an electronic signal) is not present.
Get a GPS-based theft tracking system. This will help police track and locate your SUV if it is, in fact, stolen.