1. Light - red light for dark adapted testing. Longer wavelength reds are better
2. Paint - black matte color for dark adaptation
3. General Room - no windows, under-the-door area covered so as to let no light through
4. Electrically - having the room on a separate circuit or using a surge protector; this is not absolutely necessary
5. Placement - away from large electrical appliances such as HVAC, refrigerators, elevators, etc.