Specific Campaign Guide: the One-Shot

Or, how to plan a one-shot campaign

The first question to ask yourself is what the point of the one-shot is why you're doing it.
Is it to introduce new players to the game? Is it to introduce experienced players to your group to see if they fit in? Is it because a couple usual players couldn't come? Is it because you want to try out a crazy concept or setting?
Based on this question, there are several things you should decide. Character level is a really crucial one, as may be classes and races that you offer. If you're running it for people who've never played DnD before, you'll want a lower level. If you're running it for usual players of yours, some players might want to keep their character sheets but play different character concepts. For people you're trying to bring into your game, level them to or near the current party level.

For class and race, this is less by-the-book. I've heard DMs say that classes should have at least as much restriction as a long-term campaign, since you don't have time to balance out game mechanics. I'm of a different mindset: if it's just a one-shot, an imbalance doesn't matter that much, and you don't have to find a way to work it out with your player over time. In addition, offering classes or races you usually don't could be a part of your campaign concept, such as an evil or flight-races or psyionic one-shot.

Once you have an idea about that, give yourself an estimate of how. This will directly define how many encounters you can have in your game. I suggest making one-shots largely combat focused with little "color" or roleplaying specific encounters. This is because those tend to take longer to go through with a lot of variation in both time and how events play out. For combat, you can get about one encounter per hour in. For more epic encounters, such as fighting a dragon, you might think about making that the only encounter. Furthermore, think about how much background is needed for any given encounter. After all, since when does a dragon need a reason to land and start ransacking a village?

All that said, it doesn't mean you have to just have a "they went dungeon delving" plot. The last one-shot I ran was a mystery where the party, who happened to be the next-most-powerful folks in town, went to find out what had happened to the town guard. They fought off the wolves and cheetahs in her front garden, and then killed the red dragon that had hatched and murdered her, meanwhile finding out what had happened to her.

And that's about it! Once you've got everything, you have a plan for your one-shot campaign- one that actually can be finished in one session.


So, to sum up:
a) why are you running it?
b) what level will the characters be? Should depend on a).
c) what classes/races will you allow? Decide based on campaign, players, and your preference.
d) see how long the campaign will last. Remember: ~1 encounter/1 hour