You can’t escape the need to research your book genre and do it well. Research involves reading classic and current novels in your chosen genre. For my latest book, I read every book I could find on the main topic, plus movies and online interviews, etc. Why? Each source gave me insight and information that I sifted to authenticate my plot. For thrillers in real locations, visiting in person is hands-down the best approach. If you can’t visit, then at least search photos of the area(s). I even use Google Street to get ideas and, with so many travel docs available, these help too. With handfuls of information you can add authentic details that help readers immerse themselves in the writing, especially if they have visited the place too. I have made great use of small details—the color of tablecloths at a restaurant, the plants that grow along a boulevard, etc. Here is one such detail from my new book;
“She smoothed her floral dress and settled behind a table on the waterfront, her back warmed by sun-saoked stonework along the old city wall and her front sheltered behind potted color in raised flower beds. Touts trolled Split’s swanky Riva Boulevard, and beggars fossicked through the Spanish broom, plucking its yellow flowers to sell to restaurant clientele in the evening. They left Claudine to herself.” [pg28]
If you have contacts living or working in the area you are writing about, ask them if they would be happy to check pages from your manuscript that refer to their location. I did this for my first novel, using contacts living in Milan, southern France, and Israel. I also added them to my Acknowledgements page.