Stuff to bring, things to keep in mind when investigating..
Bring a level. A little cheap one is fine. So if doors open and shut on their own, you can check to make sure it's not just because it's not hanging properly. If balls roll around, check to see if the floor is level.
Don't wear windbreakers. They make swishy sounds that can sound like whispers in an audio recording. Also avoid shoes that squeak or make other noises.
Don't wear or carry reflective materials when flash pictures will be taken. It can create weird effects.
Be aware of reflections off eyeglasses or other shiny things. If you take a flash picture of a cut crystal vase, expect to see what look like orbs flying around the room.
Voice stamp everyone present - state name, say a sentence, sigh and cough. I hate having to discard what might be a good EVP because it also might have been someone (living) who was whispering or sighing.
Take a photo or video of everyone present, what they are wearing and carrying.
Handy for debunking.
Eat a light meal or snack so stomachs don't growl as much. It sounds like a demon.
Don't put too much emphasis on emf readings alone. Don't get excited when the light comes on. Use emf readings to investigate areas where activity is reported. If it reads high, check for electrical wiring, appliances or other causes. Otherwise, I only consider emf readings when they are in conjunction with something else that seems out of the ordinary (sights, sounds, feelings). Alone, it can have lots of explainable causes.
Try to ask questions that can generate more than a one-syllable response. One syllable can sound like almost anything that you may be expecting/hoping to hear.
When attempting to capture audio outdoors, use a wind screen.
When making a video to share your experiences, please don't play music during the actual sound clips from the investigation. It's distracting. That's the point of the ones on tv, but we're not on tv.
Matching black t-shirts and clever group names don't take the place of critical thinking and proper analysis.
Ceiling fans. I see so many videos where it is insisted that there were no drafts. Yet I can see the ceiling fan just spinning away. It can blow dust around, create reflections, cause things in the room to move and sway.. Turn the fan off first.
Certification? There is no official certification at this time.
The spirit box sessions leave me feeling unsure as to whether I'm hearing random radio signals or what. I would need to hear several syllables across several frequency sweeps to be convinced of anything else. I believe it's possible.
Always keep original of audio, video and photos. Then go ahead and sound filter, crop, or otherwise enhance it for clarification; but always present it as such. I am unable to analyze ghostly photo without EXIF information available.
Breath shows up at night in warmer temperatures than many people realize. Even in low 60 degrees I've been able to capture "ghostly" mists by normal breathing just before taking a picture. Depending on its proximity to the lens when the photo is taken, it can appear huge. The technical photography term is "forced perspective."