My campaigns last years; my last two combine to account for over a decade. This could mean that I’m crushing these campaign designs, or else that I have no data pool of note, I dunno. But for me, essential ingredients include:
*What’s the soundtrack? I compile huge lists of songs for each big arc, then DJ the moments spontaneously, recognising that oh man, the players are creating a moment that X track would just slay. A soundtrack pile also helps me set the tone palette in my head.
*What do extremes look like in the world? What’s cruel? What’s funny? Any genre can have every narrative ingredient, but cyberpunk funny looks different than desperate expedition in a flooded world funny.
*What is the scale of the stakes? This influences the players’ style so much. If you set the scale as ‘find the true king and prevent mass revolution,’ then whether or not you’re going for action, melodrama, or comedy of dunces, things are going to trend broad. If you go micro and weight tiny moments with big freight, so will players.
*What would happen if the players didn’t exist, and how would that already be a dope story? If I know the big forces colliding, what everyone wants, and who is likely to prevail if the characters don’t F things up, then I’m ready for them to come F everything up, and what would’ve been one story becomes something else entirely. The ‘Inglorious Basterds’ principle, if you will.