I’d like to create a list of techniques used to make active locations. This is explicitly about design or prep, not about improvisation. How do you build a place that actually feels like one and not just like a convenient backdrop for the characters? (I don’t have a lot of experience with this. I’m inspired by past discussions of modules and Adam Koebel talking about Mothership).
Stuff I’d say belongs on the list:
Movement tied to encounter tables.
or
Law levels. Like the ones in Traveller for example. Interestingly, I feel that Dog Eat Dog does something similar: “the Record—a history of the island, as defined in a series of Rules. These Rules are the unspoken assumptions that govern interactions between the Occupation and the Natives.”
"If the PCs do nothing"-style timeline/front/clock. If the PCs do nothing, (1) the key is stolen from the watchtower, (2) used to activate the orrery and (3) all children under 9 turn to glass across the city.
NPCs with set agendas and daily routines.
Detailed maps including tangible obstacles. The City of Hex is probably the most extreme example of this.
Faction mechanics. From Dream Askew’s Setting Elements (someone plays and makes moves for the “Society Intact” or the “Outlying Gangs”) to a kind of separate play with (sub)systems like this voting mechanic for the factions in Traveller’s Nomads of the World Ocean: