Choose the location. Ghost photographs are often shot in places that look spooky. If you are trying to fool people into thinking that your own house is haunted, then conduct the photo shoot at home.
Place your camera on a tripod and pose the participants. The "live" people will have to remain extremely still for about 10 seconds. The "ghosts" will need to run out of the frame at the appropriate time.
Set the exposure for at least 10 seconds on your digital camera. Tell your "ghosts" to move out of the frame when you say, "Go!" Once the shutter is open and the picture is being taken, say, "Ready, set, go!" Make sure that your live people stay completely still.
Upload your photo to your computer. You will have a realistic looking photo of live people and a few blurry and translucent ghosts.