I have prepared (most of) a campaign reference document for each, all of which are radically different from one another. And they are so different because I'm looking to create different experiences with different groups with different expectations and needs.
For the purposes of this article, I am going to talk about three stages of campaign development for each:
- The Campaign Goal: this is where I talk about the experience you want to offer your players. Gathering inspiration, etc.
- Player Data: after you know what kind of experience you want to offer, the next step is to figure out what you need to tell your players about the world to get them making characters, giving you ideas to work with, and building excitement.
- DM Data: Once you have your players making characters, asking questions, and possibly "front-loading" campaign material for you, you need to figure out what else you as the GM need to know to run the first couple of adventures.
Ultimately, some of your most important world building has to happen after the second adventure, but that is a topic for later.