There are several ways to dig into your subject in order to find what you need to polish the little details that bring realism to your writing:
#1. One of my favorites is to read other books! In doing so, make sure you do not get so lost in them that you forget to write your own. This can also be a concern with #2.
#2. The Internet. My Very good friend,
has made it possible for me to tramp through the Amazonian Rainforest, plunge into the depths of the Corycian Cave on the slopes of Mount Parnassus, explore traditional homes of the Joseon period in Korea and creep about the ruins of a mysterious castle in Ireland. I’ve learned about obscure dialects, archaic religions and fantastic prophecies of the future of mankind. All of this has been necessary to create a background of veracity for my writing. Give your reader a tour of Agra, taste exotic foods in a village market, smell the blooms of a distant island. Let them hear the Bells of Notre Dame ring out and feel the sting of an Arctic blizzard! But makes sure the details are correct. (I look those things up, AND have tried some of the recipes!)
#3. Travel. If you can, making a visit to the location(s) where your novel is set can help by allowing the reader to connect to something familiar. We’ve all seen the skyline of New York, and who doesn’t recognize the Great Pyramids or the Eiffel Tower? Giving a clear description of a place setting allows the reader to anchor themselves, and hopefully, overlook the fact that you have a fairy, dragon or witch gallivanting about. No time or money to travel? No problem! See #2!
#4. People Watch. Use little quirks you observe, quaint turns of speech, facial expressions, tics, twitches, unique laughs… there’s no end to it! Characterization is EVERYTHING. Give your readers genuine characters they can love, hate, scold, empathize with — as long as they engage with the people you create, you’re doing it right. If your ancient, teen-aged appearing, shape-shifting alien, mind-reading heroine can make a basic connection in some way that makes her seem more human, you’ve won half the battle. Put her in an authentic setting (or one with authentic nuances), give her relatable emotions and conflict and the result will be a story that allows rationality to take a back seat and disbelief will be forgotten.
All that will be left is your wonderful tale.