Here is our best list for common sense items when Ghost Hunting:

1. Keep a clear head. This means no alcohol consumption or use of any controlled dangerous substances.
2. No smoking. The possibility of it being photographed and mistaken for ectoplasm is high. In addition, if you're too busy inhaling that acrid tobacco smoke, your nose is dead to any paranormal smells you might encounter.
3. Don't trespass. Always have permission to conduct an investigation.
4. Don't jump to conclusions. You always want to make sure you consider all possible explanations, natural or otherwise.
5. Be open-minded. If you think there are no ghosts, then obviously for you, there won't be. Skeptics bring negative energy that could compromise an investigation.
6. Research. Always make sure you try to find some information on the place you are investigating before you investigate. The history of a place, be it a town or a single home, can shed some light on why a place may be having paranormal activity.
7. Either remove the camera strap or wear it around your neck. It's amazing how many times camera straps have been mistaken for ghostly photos. In keeping with that theme, make sure long hair is pulled back, and all fingers are away from the camera lens. Simple, but important.
8. Make sure all of your equipment is in perfect working condition. Dust and dirt buildup can cause problems. It saves you money overall to maintain clean equipment.
9. Bring a flashlight with extra batteries. You never know when that flashlight, camera, recorder, scanner, (you see where I'm going) is going to run out of juice.
10. Bring along a notebook so you can write down your observations. It is also a good idea to keep a log of your investigations. I recommend keeping track of moon phases, weather and solar weather.
11. Never go alone. Having more than one person insures that nothing will (hopefully) go unnoticed. It is also good to compare notes on an investigation and because you have more to fear from the living, there is safety in numbers.
12. Write down your observations before sharing them. This insures that your story is not subconsciously altered by what someone else tells you.
13. In cold weather, hold your breath while taking a photo. I've seen so many photos of "ectoplasm" that was nothing more than breath in cold air.
14. Do not take photos while walking or driving along a dirt road or path. This can lead to photos of dust particles and not orbs.
15. Do not take photos in rain, snow, sleet, freezing rain, or fog. It may also be a good idea to keep track of the pollen count in spring and summer and avoid photos when the count is high.
16. Remember you are out there to record paranormal activity and to have fun. But DO NOT be disrespectful in areas such as graveyards or old buildings. No horseplay or loud obnoxious behavior. Remember, this is not YOUR home.
17. No Ouija boards.
18. Talk to the spirits and ask for their permission to take their photo. I also try to explain that I'm not there to be disrespectful but that I am trying to understand them.
19. Do not take photographs with the camera pointing directly at the sun. This can create "sun dogs" (hexagon shapes) that are sometimes mistaken for orbs. This will also create "sun flares" where the red lines in your picture may occur that are confused for spirit energy.
20. Don't take photos of reflective surfaces. This would include mirrors, glass windows, and even still pools of water.