She rejected on one hand my usual “bottom-up” advice ripped from the middle sections of the 1st ed DMG (simple starting town plus dungeon plus small scale map of places between) and my rather more involved “go out and read these twenty real-world books on social/economic history, physical geography, mythic cycles yadda yadda” type advice. She, instead, wanted sources that could help her create enough of an interesting homebrew world that it didn't feel completely like a movie set backdrop–and here's the real groaner--but digestible enough to be read in a single (if long) night.
It's a daunting question.
Here's the best my wee brain can come up with. First a little quick general advice:
Practice Just-In-Time, Long-Haul Creation. Create just enough for you to feel comfortable in answering the questions and anticipating the choices of players. So your comfort level is above just a town and dungeon, figure out what your level of questions is “just enough”. Things like the name of the realm, a few stereotypes about its people (these can be contradicted in play after all), the big ticket geographical features (a volcano-ridden long chain of barrier mountains, poison fungal wood etc), the local enemies/threats and the like.
Now that you have a starting base, think of the first session and its prep as the beginning of a long journey: one step by enjoyable step you figure out more and more of the specific details. Give yourself room to breath and grow. Don't paint yourself in a corner.
Group by Levels of Detail. Related to the above, even if you want more than just that small scale map, it makes sense to group what you actual detail to that smaller scale in the first few sessions. Put more attention into the NPCs, unique features, and general lay of the land to that small, bounded area. Think of it as the "zoom function", putting in more to the places that the PCs are likely to visit.
Play 20 Questions. Jeff Rients famous 20 campaign questions to ask yourself is an excellent (and quick) way to put your head around the types of setting details player may want.
Now the actual question, what to read:
Ed Greenwood's “Plan before you play” Dragon magazine #63 and “Law of the Land” #65. The former article (really Greenwood was at his best before Forgotten Realms was published) is a great little thought exercise walkthrough: draw up a vague regional map, jot down some countries with a few unique characteristics, then extrapolate relationships between these realms (what are the trade routes, who is likely to go to war with whom etc.) A quick and dirty way to think holistically about how the region hangs together organically.
The second piece is another one of my all-time favorites. Ostensibly it's about the rather dull subject of creating legal systems, but the piece wanders so far off the reservation that it hits all kinds of subjects from weird local folklore/customs to how to develop interesting political intrigues. Again another piece that is both interesting and thought-provoking in getting you
MAR Barker's “Create a Religion in Your Spare Time for Fun and Profit.” Again a piece that's more about thinking through a broad range of questions than direct “how to” advice (I find these types of articles far more inspiring and provoking to my creative process than the rather canned, predictable advice you get from most gaming material). Barker takes on how to create more than just cardboard deities of a vaguely familiar real world type, but how to start a thought process that weaves in a coherent religion/cosmology/mythology that relates to the “actual” world of its fantasy practitioners. (Something for the longhaul creation process).
Oh great wisdom of the collective hive mind, your turn to help a sister out. I'm sure I am blanking on any number of useful resources. What short readings/tips/tools would you suggest? And what makes them great for this purpose?