Lessons from the trad trenches, or How to structure a scenario

In the past few weeks I've been thinking a lot about game structure. I feel quite safe in running a dungeon crawl1 since it's the easiest one, and also with running mysteries, but there is the "scenario" structure of games that isn't as intuitive. This is the structure you find in pretty much any non-D&D game, from your average RuneQuest session that does not involve delving a perilous place, all the way to more modern games like Apocalypse World and its family. For that purpose, I have tested it out on my And in the Darkness, Hearts Aglow campaign to good success. Thus now I feel quite comfortable running either of these three structures, but I still have a bit of difficulty regarding the prep part of the scenario structure, and so I decided to read the DM sections of quite a few different RPG books and check what their recommendations are, and what language they use. I won't list all of the ones I looked at, but it was around 10 of them, including pre-Forge ones like RuneQuest and…