Write down one or two paragraphs that capture the essence of the book. Focus on the most important themes and plot aspects, and summarize the book in a succinct but compelling manner. This will provide you with a starting point to help you narrow down and visualize what matters most about the book.
Make a list of all of the nouns used in your paragraph followed by a list of all of the verbs.
Use your two lists to see if you can find word combinations that sum up the book in an accurate, eye-catching way. The Write and Publish Fiction website recommends this approach as a way of truly narrowing down the most relevant words possible.
Write down additional words similar to the ones on your lists. For example, if your initial list included the word "mysterious," you may choose to add "enigmatic" or "unknown." This will give you more word opportunities if your initial list fails to provide you with good title ideas.
Try combining your new words to come up with a title. Even if you do not choose to use a noun and verb from your list, you should now have enough words available to come up with potential titles that capture the essence of the story while grabbing a potential reader's attention.
Make a list of several potential titles.
Show your list to friends and relatives and ask them which title has the most appeal. Outsider perspectives can help you to narrow down your options to the most compelling title.
Choose a title from your list based on the feedback you receive as well as your own personal inclination.