Many people talk about about reduce crime in a rental property. Here is a great link on a certification. The tips you learn are very practical points. They even have training classes and certification. They also tell you things to look for that are tell tale signs of illegal activity on your property.
http://www.crime-free-association.org/multi-housing.htm

most neighborhoods are relatively stable until YOU MOVE YOUR UNRESTRAINED dont give a damn about the older neighbors who become afraid of your TENANTS. no manners, bad language even toward the police. since we now know whereabouts you lie your head at night i wonder if i could redirect their loud late dopesmoking parties your way…you might get an academy award for that look on your face when you open the door.