First of all, take a look at your properties landscaping. Do you have many trees and shrubs surrounding the home's entrance or windows that are shielding them from the view of the street? If you do, an intruder may easily be able to hide behind them and break-in, unnoticed by neighbors or passersby. Placing fencing around your property can work to discourage a thief but, again, you will want to check that it doesn’t act as a shield for hiding behind.
Another way to make your home unappealing to a thief is with good, solid exterior doors and windows. Make sure your doors are fitted with quality deadbolts. Windows and doors need to be in good shape and show no signs of deterioration. As an extra security measure, you may want to install heavy-duty wire screens or window bars. If you do this, though, make sure that all the homes occupants would be able to exit the windows easily in an emergency.
Outside lighting is another way to deter a would-be intruder. Fit motion censored lighting to every side of the home, leaving no areas of darkness. It is also a good idea to leave some lights on in the house if you are going to be away so that you give the impression someone is home.
Sliding glass doors are another easy entry point for a thief. Fit locks to both the top and bottom of each door and, as an extra measure, you could also place a piece of wood like a cut off broom handle into the tracks of the door.
These simple steps will go a long way to making your home uninviting to a thief.