Make lists and tables
Some content exists in a quantum state. The sentries walk a perimeter. The cave bears might be out foraging. The ruin is vast and you can't be bothered to plot out where each danger, discovery, or NPC is at every moment.
Put this sort of content into a list (or lists). When the PCs enter a new area, or when you want to make a GM move but aren't sure what to do, then pick something from this list.
If you like, turn the list into a table. Assign numbers 1-6 or 1-12 to the options and have a player roll the Die of Fate to see which option they get.
For examples, see the many regional and site entries in Book II.