So You Want to be A Game Master
By Justin Alexander
This book was very D&D centric, but even so it's clearly written and actionable. Many of the concepts apply more broadly.
Takeaways:
4 factions taking turns in the spotlight
Social situations - ideally 15 notable people with 8-10 topics, mixing trivial and important. Can also use evening events for conversation (did you see Astoria run out in tears? What could Rupert have possibly said to her!)