Actions taken daily to ensure your safety. They are simple acts you train yourself to do that significantly decrease the chances of a criminal choosing you, or your property, as his target.
They can range from remembering to enable your "walk-away" security measures (i.e., locking doors, windows and closing your drapes when you leave), never leaving your car running and unattended, to not leaving valuables in plain sight on your car seat, to looking around when you enter a fringe area or before you reach your car Such habits are not difficult to ingrain and, within a week or two, become automatic.
The reason they are effective is that they either remove items of value from sight, deny easy access or complicate things for the criminal. Moreover, they give you early warning that something is wrong. This is essential for foiling the criminal's attempt to develop his plansunnoticed and without opposition.