Once upon a time, I was a young DM playing Dungeons and Dragons 2nd Edition. Yes, that does date me a bit. Long before Curse of Strahd was a thing, there was the Ravenloft box set, which contained all the world building and additional rules you need to play in the demiplane of dread. Vampires, ghouls, zombies, and mists that would wrap you up and take you away. It had all thing things it needed to be scary.
I ran exactly one quest set in Ravenloft and it bombed. I was so disheartened that I would not try to introduce horror into a game for many years after. Not only were the players in no way scared, they didn’t really enjoy themselves and we’re rightfully bitter that I ripped their favorite characters away from their lives and inserted them into an inescapable teenage angst depression death trap.
I did have a certain style to me…
Looking back, there are a few major reasons I can see as to why it failed. Firstly, I was not writing for the art form. The players spent the night in a haunted house, each in a different room. They each had a nocturnal vision of ghosts in their room. The problem was they were watching a story they weren’t a part of.

Wooooooo, watch how this ghost died and how it is eternally tormented. Boooooo, scary, right? In retrospect, I was really writing a crappy short story and not an rpg adventure. The characters just watched what happened and then fought some things in the cemetery. There was no reason to be involved until it came to some generic encounter among the graves.
One of the other problems was pacing. Things just instantly ramped up, leaving no room for atmosphere. Horror is something you need to build to, as shock and gore are things that translate much better to a movie screen than a game table. Just instantly throwing tropes at something isn’t going to make it scary. If you’re going for B horror movie campiness, go for it. Otherwise, you’re not going to get far.
All that said, lets discuss some elements that will help. I’m far from a master of the genre, but I have learned some things that angsty teenager James running Ravenloft didn’t know. Of course, I’ve forgotten some pretty cool stuff too.
It’s not what you see…

There is an actual reason why fear of the dark exists. I don’t think there has been an actual case in history where darkness has come alive with tentacles and actually harmed anyone, but I’m not a historian. The actual reason is that it obscures the senses. The human brain is still afraid of predators and predators hide in the night.
But it’s not the predators that we’re reacting to when we feel unease in dark places; it’s the threat of predators. It’s the unknown. We don’t know whats out there and that is what bothers us. We can react and adapt to a threat we see and experience. An unknown threat just starts our anxiety buzzing, getting us ready for a fight or flight we may or may not need.
How do we apply that to an RPG? Throwing ghosts and zombies at the players is not the way. That gives them a tangible threat. DnD players know how to handle that. Instead, don’t tell them what lurks out there in the dark. This is a great opportunity to show and not tell.
A far away soft whimper, scratches from the other side of the wall, a corpse with gizzly slash marks but no sign of what made them; none of these give a tangible threat. Call of Cthulhu is great at this and part of the reason is that the games are a mystery. You spend most of the game trying to find out what the true root of the horror is, which leads us to our next point…
Make it a mystery
Think of pretty much any horror movie you watched, even the slasher films. There is going to be some mystery involved. Likely, you don’t know what the monster is or who is actually the slasher. If you do, you probably don’t know how to defeat it. This ties in with the fear of the unknown; you’re powerless to stop the killings if you don’t know who is behind them. You can’t stop the killer if you don’t know how.
Give room for humor
Player’s are going to make jokes. They’re going to have fun. This is a big reason why people play RPGs. It’s easy to get discouraged when you’re trying to be dark and ominous and your players are goofing around.
First, be easy on yourself. These things take time. Secondly, give this type of behavior room. Trying to fight against it will be counterproductive. Let the conversation happen and then bring everyone back to the game afterwards. Defiantly don’t berate the players. That is a good way to ensure no one has fun.
Instead, learn to capitalize on the moments when they aren’t. Use the spotlight when it naturally falls on you. If you find the players really engaged in what you’re saying, you’ve found a lead. Follow it.
Vary the way you speak.
Talk slower.
Take a dramatic pause. Let the weight of your words sink in.
The more you practice, the better you’ll get at recognizing these moments and capitalizing on them. If you have some great players, they will too. It’s a beautiful dance when it comes together, but you just can’t force it.
Atmosphere

Ravenloft is known as the Demiplane of dread. Right in the title, this gives you information on the atmosphere there. With horror, atmosphere is key. Sights, sounds, taste, sensations… these are your seasonings. Don’t make bland food.
“You see 1d6 zombies. Roll initiative.”
This is lacking context to make it scary.
“The cold stone room is silent, except for a skittering that is punctuated by the occasional sounds of cracking and squishing. As your eyes adjust to the light, you see five horrific caricatures of humanity. These walking corpses with sunken features amble about the room, chewing on decayed remains. As the scent of decay threatens to overwhelm you, you realize its best you don’t think of what their meal is. “
“Roll initiative. “
What sounds are heard in that haunted house? Are the walls bright orange, or are they muted grays with water stained corners? I bet it’s musty.
Constantly reinforcing the atmosphere of a place and scene really brings the players into it. Let them know just how dreadful the demiplane of dread is.
Pacing, pacing, pacing
I’m a firm believer that pacing is essential to pretty much any story. With horror, this is doubly so. As with most things, I’m a fan of the slow build. Don’t start with ghosts in the room; start with clouds lazily drifting in front of a full moon. Give time for the dread to build, using the down time to build atmosphere as mentioned above. Once you get to the real terror, the players will have had plenty of time to let the fear set in.
One of the fun things you can do with horror gaming is varying the pacing. Think of when the slasher suddenly pops out of a closest during a otherwise calm scene. This will take a bit of practice to make work, but it’s pretty rewarding when it does. The key here is to give your players the opposite of horror.
By that I mean, you want them relaxed. Soothe your players, speak in your calmest voice. You don’t want them to know what’s coming. You’ll notice many verbally transmitted ghost stories will use repetition for this purpose, repeating certain phrases. It has a strange paradoxical effect of settling the audience, which in turn gives them a slight anxiety as they wait for the other shoe to drop.
When it does, make it sudden. Smack the table, change the tone of your voice. It’s not easy, but if you manage to get your own personal formula down, you’ll be looking pretty cool.

There are plenty of other techniques out there, of course, but this is a start. As with anything, it’s not reasonable to expect to be great right from the start. The best technique you can utilize for horror is practice. Be okay with not being perfect. It’s the only way to improve.