try to get decorative items that are not soo expensive. instead of getting expensive ones.. go for cheaper and smaller things such as pots and crafted items that no theif wants to take as they are no crystals or diamonds..

on the other hand, if you have expensive items.. try to gets ones that are too heavy and need a car or some truck to be taken..or ones that get attached to the floor or wherever they are placed.. sticking them up with glue is also a nice idea

check out http://www.aboutfurniture.org/index.php for more on decorations and how to handle them