[david914]

Trap the door (door contact), install dual tech (PIR & microwave - less chance for false alarms) motion detector(s) and make sure you have a LOUD siren. Cameras are also good. Thieves don't like attention. Signage stating you have a monitored security system is always a good idea, even if you don't actually have a security system. You want to discourage would-be thieves and send them on to an easier target. If your existing security panel is operable and has a spare zone or two, you just need to add the aforementioned sensors to your panel and you're done.