Lock your doors and windows!  Use high quality deadbolt locks on exterior doors.

Use heavy duty strike plates (part on the door jamb the bolt from the lock slides into) with at least 3" screws.

Use a secondary blocking device, such as a wooden dowel in the tracks of sliding glass doors.

Use timers to turn lights on/off when you are not home.

On windows, use secondary blocking devices such as a wooden dowel or commercially available in the frame pins or other high security window locks.

Find a trusted neighbor and make plans to keep a eye on one another's property.

Use security or motion lights to keep the perimeter of your home well lit.

Consider a good quality and well maintained security alarm system.

For valuable items, make a photographic record.  Include the brand, model number and serial number (if any) with the photograph. Store these copies in a safe deposit box, or with a relative or friend.

Keep foliage trimmed so as not to provide concealment area to would be thieves. 

 Consider planting prickly or thorny decorative plants under windows.  Let the grow to the height of the bottom of the window.

Report suspicious activity.