Always lock your truck. Whether you are running into the store for a few minutes or parking it right outside in the driveway, locking your truck is always a good theft-deterrent.
Park your truck in a well-lit, secured lot. Look for places with excellent lighting, lots of people around and a security guard or security-camera system.
Use your garage. Clear out the boxes of old clothes to make room for the truck your garage was built for.
Avoid leaving your truck running unattended. Drivers are prone to doing this on cold days when they are planning on "just running in" to some place, but a running truck is ripe for theft.
Leave the windows of your truck rolled up. It is easy for thieves to reach into a truck through open windows to unlock your doors. Even if the windows are open just a crack, thieves can use a special tool to reach through and press the unlock button.
Invest in a security system for your truck. Electronic engine immobilizes prevent the engine from running when an electronic key is not present. Audio alarm systems alert passersby to a theft in progress. Tracking systems follow your truck wherever it goes, so police can track your stolen vehicle.
Find and record your truck's VIN (vehicle identification number). It usually can be found on the driver's side, either on the dash or near the latch mechanism of the door.