In the U.S. alone, a commercial robbery is committed every four minutes. That's more than 100,000 robberies each year. Some suggestions for robbery prevention:
Be sure you have adequate lighting both inside and outside your business.
Exterior lighting should illuminate dark areas around your building and parking lots.
Interior lighting should be adequate enough to allow people outside your business to see people inside.
Place a fence or hedge around your building to discourage robbers by presenting a significant hindrance to getting away.
Place security signs and stickers on points of entry to serve as deterrents to robbery.
Install silent alarms to notify police and give them a better chance to catch perpetrators.
Install some form of cash register protection.
Install security cameras, which not only serve as a robbery prevention tactic, but help with identifying a robber after the robbery has been committed.
Utilize a safe with a drop mechanism that allows you to make periodic drops during the day to minimize the amount of cash in your registers.
Always drop large bills immediately and publicize this to discourage potential robbers.