Contact the local police station in the area and alert them of the fact that the property is currently vacant. As a tax paying resident of the local municipality, the seller has a right to request that the police keep an eye on the property while it is vacant. Many stations will be happy to take note of the vacant property and make additional drive-bys in the neighbourhood. Contacting the local police station can reduce the possibility of a problem with the home.
If the home does not already have an alarm system, installing a system will protect the property while adding value. Security is a top priority among buyers, so homes with security systems generally sell for higher premiums.