There are several ways to do this, but in general you want this to be short and sweet but still cover the things you need.
Matt Coleville talked about this literally yesterday in the video found here:
Only this is more about pitching the game to players, and less about making the plan itself. Still, it is good to see because a good pitch should be able to bring you back into what the campaign was meant to be. You can find the handout Matt talks about in the video here.
Personally, I've become a huge fan - and user - of the style of campaign planning used by Sly Flourish for his gnoll campaign (a game I really want to run myself actually.)
How it works is simple. And when done you'll not only have a campaign sketched, but you'll have something to hand your players to get them ready to go too.
Part 1: Your Campaign In Three To Five Words
The first thing you need to do is pitch the campaign - what it is about - in three to five words. You can use more words if you need to, but really this should just be one sentence (or even a fragment.) This is the core idea. Think of it like the final objective for the game. For Sly Flourish's Gnoll campaign he used "End Yeenoghu's Hunger." For my own pitch, I used "Save Hedingham County."
Having this, and having it brief, is good because it gives you a strong, simple core. Everything else you're planning should build towards this.
Part 2: Six Truths That Make Your Game Different
Odds are if you're running an RPG your game brings with it a lot of assumptions about the world. The players have expectations. If you say you're running Star Wars, your players are going to expect to be in the Star Wars universe. The same if you say you're running D&D, L5R, Traveler, or any other game. There are expectations.
That's good and fine. We want that. Those expectations give us a base line to work with. Now what we're going to do is give six truths about the world that separate this game world from other game worlds. This information is going to be publicly available to the players, so don't hide twists in here. It is one thing to say "There is a cult in the shadows" and another to have "Father Magda runs a cult of corruption" where part of the campaign is going to be discovering Father Magda is running a cult.
For the "Save Hedingham" game I had the following:
- All of Lorwyn (Kingdom) has been embroiled in a war to the South for the past fifteen years.
- Taxation to support the war effort in Hedingham has many of the poor and working class fearful of losing their homes, some have already lost theirs.
- Many elves and dwarves have been moved to ghettos called alienages with the forests and mountains declared to be “State Land vital for the War Effort.”
- Outlying farms and homesteads report sightings of goblins and other monsters on the outskirts of the County.
- After Count Heding’s death, a Lord-Protector was appointed to oversee Hedingham County until such time as the Count’s eldest son returns from the war to the south where he fights at the King’s side.
- Rumors speak of a cult at work in the shadows, preying on the sick and downtrodden.
That's it. This is a D&D world, but those six things are there to show the players what is going on with the world. This is also information for the players to have in mind when making their characters. Maybe someone wants to be an Elf. Now they know there are elves in the area, but they are not so separate that they don't have to bow to the whim of the local government. They also know that they can expect the situation for their fellow elves to be a little bleak. These six things also lay some ground work for the Players. They know there will be goblins and monsters. They know somewhere there is a cult at work. They also know that the people are under heavy taxation to fuel a war effort and that the local lord is dead with a surrogate/regent in place while the heir is away.
Part 3: Player Goal
With the six things, we also want to plan a goal to give the players. This is basically to ease problems with character motivations and interests. It tells the players something to keep in mind when making their character to make sure their interests, and the games' interests, are in line.
This is also simple. For Hedingham I wrote this: My character wants to work together with the other PCs to ease the suffering of the people in Hedingham County.
By giving this to put into their characters as a goal, the players know what this game is about. The game will be about saving Hedingham by that I mean helping the people out. Considering the people are dealing with heavy taxation, goblins & other monsters, displacement from their homes and seizure of property (for elves and dwarves at least), and a cult, there is a lot of ways that could go.
We don't give away too much, but we also should not run into the problem of a character showing up looking to do something that is cross-purposed with that central goal. And if they do, we have that we gave that information out to lean back on as something we were looking for for the game.
Part 4: Three Fronts
Everything above this point can be given to the players. You don't have to give the quick pitch, but you can if you want. From here on though, we're working on the antagonists and behind the scenes stuff.
Dungeon World has the concept of Fronts in its game. The word comes from the phrase "Fighting a war on two fronts" and it is a quick way to set up one danger that the players are going to have to deal with. The Dungeon World book explains the concept better than I can, but the idea is to sketch out sources of opposition or danger for the game. To do this we're going to define five things: The name of the front, the front's goal, and three grim portents.
Name and goal are fairly easy. Those goblins I talked about? They're a front. Their goal? Well, they're goblins, so they want to kill, and eat, and reproduce, and consume the whole country side. Why? because that is what goblins do. In fact, let's use that for a front.
- Front: The Screamshred Goblins
- Goal: Kill, Eat, Loot, Reproduce, Expand, and Consume
What about the portents though?
The portents are basically the milestone steps for the front if the PCs do not stop the front. So the PCs hear about goblins, but are otherwise occupied and don't hunt them all down. The grim portent happens. The PCs continue without really dealing with the goblin threat. The second grim portent then happens. Still nothing? The third happens. At this point the situation is pretty dire. If the PCs stop the front, then you have to go back and change plans. You should be ready for that anyhow.
Considering we already started the goblins, let's finish them up here:
- First Grim Portent: Outlying farms and homesteads are attacked and razed by goblins
- Second Grim Portent: The goblins abduct a number of children/adolescents as part of their raids
- Third Grim Portent: The goblins attack towns and villages, sacking them completely.
To reiterate the above with the example, the PCs have the truth about goblins. They don't investigate (and it should come up in game) the Goblins will start to attack homesteads and farms that are isolated. If the goblins aren't dealt with, they'll start to steal children in their raids. Then, finally, they'll have enough numbers to be an actual threat to the towns and villages in the area.
I recommend having three fronts. Two can work together, or none of them can. Three gives you variety in threats though, which lets you add depths to the campaign by what each threat highlights and brings into play. It also means you have three wells to go to whenever you're stuck for ideas on what could happen in a session.
Part 5: A Loose Outline
Finally, you make a loose outline for your game by however you want to break it down. For D&D and Pathfinder doing a level by level breakdown can work. The idea isn't to set a plan in stone, but to give yourself an idea for order of events. You may have to throw some or all of this out at a moment's notice in game, and that's fine. That is why we're doing a loose outline and quick sketches. Not full detailed planning.
I recommend starting with your first and last item. The literal beginning and end of the story. My Hedingham proposal is for a level 1 to 10 game. My outline starts with
Level 1: The PCs return home to Hedingham after years away at the war to find a lot has changed.
It then ends with.
Level 10: The PCs confront the Lord-Protector and their Elite Guard
With that I have my start and end decided. Now it is just a matter of how do we go from the PCs coming home to find everything is in a sorry state, to them facing off with the Lord-Protector of the area? What has to happen for that to happen? A good question to start filling in the gaps. Once this is done you should have about a page. That is plenty. You can file it away until next time you need a game idea and it should have enough to get the brain juices going again. or you can use the Six Truths and PC Goal to have players start making characters, and then get to work on Session 0 and Session 1 to get things going. The plan will help you find your way should you get lost.