I use effects and noises, and even specific commands actors shout out at unsuspecting visitors. For example, in one room I have an antique telephone on a stand (next to our coffin). The actor in the coffin has a plunger switch in the coffin with them that rings the phone. This lets the person in the next room know someone is coming in. And it adds a little to the room with the coffin.
In another room, I have an actor that yells to passing patrons to "Look at me" as they begin to enter the next room, alerting the actor in the next room to drop a panel. Works every time!
Travis "Big T" Russell
Big T Productions Inc
Owner and Operator of "The Plague" and "Camp Nightmare"
Customer Quote of the year: "Damn, I pissed myself"