Note the publishers of your favorite authors. While many publishing houses host a wide variety of writing styles and genres, some publishers are exclusive to a particular genre, such as mystery and thriller.
Ask your local librarian for advice on a new author or book. While they may not read the same genre of books themselves, librarians are a wealth of knowledge and can help expose you to authors or genres you may have overlooked.
Look at featured author areas in your bookstore or library that cater to favorite genres. As most bookstores and libraries are organized by genre and then alphabetically by author, these featured sections are an easy way to discover new authors in your area of interest.
Read the plot summary or synopsis, located on the book jacket or on the back cover of the book. A plot summary will give you a quick overview of the novel. Genrefiction.com notes "booksellers polled by Publishers Weekly and Book-Expo America agreed that the book jacket, particularly the plot summary, was the single most important determinant of whether or not a book sold." (See References 1) If the plot summary interests you, read the first few pages of the book to get a feel for the author's writing style.