It sounds obvious, but keeping your windows and doors locked and getting into the habit of checking them before you leave the house is a really good idea. A large percentage of burglaries are unforced, meaning the thieves have just walked straight in a back door or climbed through an open window. Making sure you don't leave any handy tools hanging round your back garden that'll make it easier to break in, ladders are an absolute gift.
House alarms are a great deterrent - when they're on. Many of us have them but leave them off in the night, which sort of defeats the purpose. Ok, one of the kids accidentally setting the alarm off on their way to get a midnight snack might be annoying, but not half as annoying as having your prized possessions stolen or hearing someone downstairs in your home in the wee hours.
Motion sensors are easy to install and a good deterrent, after all no burglar wants to be exposed while up to no good. The higher up you install them, the wider the area they will illuminate - just make sure they're not a nuisance for your neighbours.