Use Google Books' Advanced Search. Type as many story elements as you can remember -- character names, locations, events, etc -- in the search box on Google Books. Click the "Advanced Search" link on the results screen. Choose "Books" in the Content section. Enter a range of years in the Publication Date section. In the Subject area, include themes related to the book, such as time travel, romance or teen fiction. Click "Google Search" to display the books matching your search parameters. Check the results to see if they include the book you're looking for.
Visit your local library and ask for help. Librarians aren't just knowledgeable about books; they have the tools and skills necessary to find the book's title. Also consider visiting a bookstore. Booksellers love literature and are typically well-read, especially at independent bookstores.
Join a social website, forum or mailing list for readers. Many have special sections for members who are trying to recall the title of a book. Create a post detailing as much of the story as you remember. Someone may recognize the book and respond with its name.