Things that can fool you are high electromagnetic fields from equipment or faulty wiring, tricks of light and imagination etc. Always make sure to run everything through that type of scrutiny. "Could this be (fill in the blank)?". You want to have things like voices not heard at the scene but picked up later on film, shared witnessed sightings etc. The best part about the paranormal is knowing that we don't understand anything about it today, but may in future generations. The supernatural of one generation becomes the natural of the next. Keep an open, but skeptical, and curious mind about such things.