FAQ: "What kind of research do you do for your books?"
When it comes to the base mythology of Nyeusigrube, I do very little active research. I grew up on horror books and movies, so I had a general idea of the popular monsters, but I never wanted to base my world on anyone else's. I took some basic definitions- "vampires drink blood" as an example- and ran with them, incorporating bits of myth that made sense and throwing out anything that didn't work.
That doesn't mean I don't do research- it just means I don't research MAGIC.
The bulk of my research ends up being historical. Even in a story set in present day, I am often dealing with characters whose lives began long ago, since many of my characters are very long-lived. More daunting, if a story is set in anything other than modern day, the research required to make it work is astronomical.
As I write this, I am taking a break from editing Bloodwitch, the first book in the Maeve'ra Trilogy. Bloodwitch is set in 1802, in the territory occupied by Midnight. Both of those facts pose a problem.
First off, I was shocked to discover how many things we take for granted were invented in approximately 1850. On the other hand, because I am dealing with vampires, I also have characters whose memories stretch back to ancient Rome, Tenochtitlan, and Egypt, and so have knowledge of technology that won't be rediscovered in Europe for quite some time. From a research point of view, this means that instead of researching, "Technology in 1802 in the American Colonies" I am forced to research technology just about everywhere for the last four thousand years or so, and then find a reasonable way to piece it together according to my characters' priorities.
Shoes, clothes and food are, in my opinion, among the most annoying yet most crucial bits of research required for writing a period piece. From a good-writing perspective, I cannot reference things that do not yet exist to give my audience perspective ("Wouldn't it be nice if we had some toilet paper!") and it's unlikely that a character is going to dwell on something he or she would find totally mundane (two paragraphs explaining how the cotton from this shirt was imported from China by way of ship, since it is not yet being produced commercially in the southern states). On the other hand, all a character needs to do is tie his shoestrings or bite into a juicy peach, and we have an anachronism.
Fashion is fascinating, but annoying. For example, I have a female character who rides in a bodice and trousers, partially because she rides cross-saddle and split-skirts won't be popularized for nearly another century. This is not because she is a radical feminist, though I know that's what most readers will first assume when she is described (where Jeshickah falls on the feminism scale could be quite an essay!). She was born and raised centuries before the side-saddle was invented, in an era where if a woman needed to ride, she rode cross-saddle. She cares more about her horses than she does about people, and she isn't going to let idiotic modern notions get in the way of her riding.
She also doesn't care if her men wear jackets or not... but there are others in Midnight from later centuries, who do very much care, and will be just as offended by a man in just a shirt as they would be by a woman in trousers. But since most of Jeshickah's progeny rather like to offend people, this again must be taken into account when I try to decide what clothing is worn when. Blend in serpiente, avian, Azteka, shm'Ahnmik and Shantel cultures and fashions, and it's a Smörgåsbord of fun, in which I somehow need to find a way to explain to my reader, "I know you think this shouldn't be the case in 1802, but in this context it's actually perfectly reasonable," without my character ever realizing anything is amiss.
Then there are the artists. I have an entire line of artists, and thus the other day I spent about an hour researching the color blue. To be more specific, I needed to know where blue pigments came from, when each was popularized, which were considered best and worst, etc... all this for a one-line reference from a trader trying to sell Brina some Maya Blue pigment. I once spent almost as much time reading about the origin of the pencil, when writing a semi-canon drabble about Nikolas, Kristopher, Nissa and Kaleo.
They (no reference) say that, when editing film, an hour of filming and an hour of editing can be expected to yield a minute of good footage. Book research is like that. Eight hours researching ducks, duck-farming, kinds of ducks, down, etc, once yielded a solid two paragraphs in which a character is petting a duck while having another conversation. Unless you're writing Tolkien-style epic fantasy, too much information at once just bogs a story down, and pulls a reader out of the character's point of view. For that character, all this is normal. The challenge is to give your reader a heads-up that things are different, without your character ever thinking, Wow, this would be really weird for someone from 21st century USA.