Don't allow more than one user ID per machine. Deploy secure screen savers to help minimize administrative problems. Confine root privileges to those administrators who really need it. Every root privilege you provide is just another weakness to be exploited. Keep your garbage inside your building where you can maintain control over its access.
Outdoor storage invites dumpster diving.
Make your staff cooperative partners in your security endeavors, not resistant adversaries. Try participatory programs such as rewarding employees who find security problems or discover miscreant behavior. Carefully evaluate a security product and make sure it does what the vendor advertises. See what other security enhancements you can make before adding technology that needs care, feeding and management. Empower someone to take quick action in a security emergency, whether it involves shutting down a Web site or calling building security to remove a disgruntled employee.