Try to take a three-fold approach: deter, detect and delay.
Deterring criminals always starts with good locks and solid entry points. But it also includes things like making sure that you have plenty of alarm signs and stickers placed at access points and cash points. Having an alarm system may not stop criminals from breaking in, but it does make them change their plans to a hurried “smash-and-grab” type of operation because a blaring alarm means that they have a very limited time at the site.
Make sure that there are 2 or more cameras watching vulnerable areas or cash points from different angles. If criminals know that they will be recorded on one camera while attempting to disable or vandalize another camera, they will move on to an easier target. Hiding some cameras is okay, but make sure that criminals notice the cameras you want them to see.
Detect them with motion lighting, alarms and motion-based camera systems that can notify you if a certain door is opened or even if the alarm system is triggered.
Delay them with hardened entry points and high security locks. The longer they think it will take to breach your security, the more they will be inclined to move on to another business that looks like it might be an easier target.