Understand that persons who rob small businesses are usually opportunistic amateurs. Most culprits haven't much experience committing robbery. Don't wait any longer, NOW is the time to prepare. Put the robber on stage. Walk outside of the area where you do your cash transactions and take a good look at what someone looking in can see.
First impressions are important.
Don't encourage someone to rob you. You can help him to change his mind about robbing you. Think about what a robber wants. Implement cash control strategies. Advertise that you only have a minimum amount of cash.