From wisebrother.com:
1. Use a wireless alarm system. Burglars can easily cut the wires on a less advanced system. And one study of 400 convicted burglars found 60% say they decided not to rob a home because of its alarm system.
2. Put your front porch light on a timer. If you leave the light on 24 hours a day while you're on vacation, that's a TARGET for burglars, not a deterrent. So use a timer to give the impression that people are actually home.
3. If you're going to get a guard dog, make sure it's mean. Burglars don't mind small dogs or even dogs that make some noise. But they DO hate dogs that might bite them . . . and who don't roll over and let the burglar rub their belly.
4. Keep your valuable stuff out of your bedroom. Burglars usually get in and out in less than 10 minutes. And they use a good chunk of that time to hit the bedroom dressers and closets for jewelry, credit cards, weapons, and other valuables.