I liked this thought-provoking essay, "Mistaking Researching for Writing," by comic book writer Ron Marz. I'd recommend it for anyone working on a creative project and wondering whether they're doing so much research they'll never get around to writing, or so little research their writing will sound false and lack conviction.
Some money quotes:
"How much research is enough? After two decades of writing fiction, I've come to believe the answer is 'Enough to fool the audience into thinking you did a lot more research.'"
"No one wants a book report. They want a story."
"Depending too heavily upon research can be the death of imagination, or at least the submersion of it. One of the gifts of writing fiction is making it up. Revel in it."
You all know a writer who's spent months or years building a fictional world--drawing maps, diagramming family trees, classifying exotic flora and fauna--but never quite getting around to setting a story there. Maybe that writer is you. Research can become a bottomless pit if you let it.
It's an issue I've faced on all my projects to different extents.
On Mom's Cancer, most of the story was taken from my family's real lives. However, I also took a lot of notes as events happened, and researched a lot about cancers, treatments, prognoses, etc. (which of course I was doing anyway).
On Whatever Happened to the World of Tomorrow, I researched my butt off. The book covers four decades of Space Age history that I was determined to get right. For each decade I pulled together facts, figures, reference images, and original source material totaling about 3000 pages worth for a 208-page book.
Always uppermost in my mind was the fact that (as Marz said) "nobody wants a book report." If I drew a lamp post in 1939 or a fallout shelter in 1955, you can be certain I had references for it. But I tried to never rub the reader's nose in it. Instead, I hoped the cumulative effect of a thousand unconscious correct details would lend the whole book some credibility and verisimilitude. A few folks have told me that's what they like about it.
I learned to resist the urge to include material just because I'd done a lot of research on it. Yeah, it took me three days to dig up that nugget, but if it doesn't contribute to the story it has to go.
I'm working on some new projects now that also demand pretty deep research, both historical and scientific. Again, my goal is to fold all of that in so it helps the story without drawing attention to itself. I badly want to get it right. I also want to get it done.
Sometimes I think that's where Melville went wrong with Moby-Dick. Dedicating three chapters to how sailors tie knots is just showing off. More seriously and recently, I've read a couple of epically long graphic novels that I think could have profitably been cut in half if their authors had been less interested in telling us all they'd learned and more interested in their stories.
In my experience, writing and research go together. Often, you don't realize what you need to know until you begin to write. In turn, research sometimes suggests directions you could take your story you may never have considered.
In the course of writing Whatever Happened to the World of Tomorrow, it amazed me how often I needed some bit of information only to have it miraculously appear days later. Like, I'm writing about the most obscure incident or factoid imaginable, and BOOM the New York Times or NASA prints an article about it. I didn't even have to hunt for it; it found me! The same thing is happening on my new projects. The universe provides. It's almost eerie.
Do your research. Do your world building. Keep it in mind as you craft your story, but don't let it become the story. And if you story gets to a point that requires contradicting your research, and you think you can get away with it, err on the side of telling a good story. That doesn't mean you can say the first Moon landing happened in 1944 (unless you're doing a sci-fi Moon Nazi tale, then go for it!), but if you always thought your Realm of the Dragons was in the North and it suddenly makes more sense for your hero to find it in the South, make the change. It's not supposed to be a straitjacket.
"One of the gifts of writing fiction is making it up. Revel in it."