The potential buyer will feel like an intruder and will hurry through the house. Music is mellow. But not when showing a house. Turn off the blaring radio or television. Let the salesman and buyer talk, free of disturbances.
Silence is golden.
Be courteous but don't force conversation with the potential buyer. Be it ever so humble. Never apologize for the appearance of your home. After all, it has been lived in. Let the trained salesman answer any objections.