Ouija boards. Love 'em or hate 'em, they have many a story attached to them. I'm going to give a few tips to you about what not to do. I've used them in the past with minimal fuss. I actually learned to speak to my guardian spirits through them before I finally learned to listen myself.
I'm writing this post because there's been a few videos on Youtube where people play with Ouija boards and weird crap happens. Like seriously weird stuff happens, to the point the haunting forces the person to move. I'm hoping to prevent that. It's fun until someone gets hurt.
1) Above all else, don't be an idiot. Don't just play with them for shits and giggles. Don't summon a demon without an experienced demonologist/ practitioner to help you out. Don't summon something you can't put back! It's like playing with a knife. Use caution! If something happens that you don't like, say goodbye and let it be. Stop things early before things get out of hand.
2) Ask angels/guardians/Gods/whatever for protection. Say a prayer. Cast a circle. Light protective incense. Be polite when speaking to spirits through the board and always (ALWAYS!) say good bye to them when you're done. Close the circle if you've cast one.
3) Be respectful towards the spirit(s) coming through. Swear at them and they can get quite insulted. That's when the weird stuff can happen. Like I said - it's fun until people get hurt and spirits can and WILL hurt you if they're powerful enough.
4) Use a code word if you're speaking to a deceased family member. A birth date, a pet's name, their favorite color. It can help weed out the negative/trickster spirits.
There's a lot more to this than what I can write here, but those are the main points in my experience. These points can be used for pendulums, spirit boxes and other sorts of spirit communication devices. Remember. They're tools. They can help, and they can harm if in the wrong hands.
Blessed Chatting, Folks!