Ask your employees what they would do to deter theft. If they don't buy into your plans, you're wasting your time and money. Most employees want to do a good job. Watching people steal without repercussions will contribute to employees justifying their own inappropriate behaviours. Keep in mind the attraction that leads to impulse buying can also lead to impulse stealing.
Thieves are like good customers.
Thieves are like good customers. If they get what they want, they'll be back. While we may fantasize about free shopping trips, thieves don't have to. Mutual aid is another useful tool to have when fighting criminal activity. Be a good neighbour.