Comp titles are something about the publishing industry that people don't spend much time talking about. They play an important, but confusing role in book sales and most authors find them annoying, but bad comp titles can do a lot to hinder your book.
What are comp titles?
The term is short for competitive or comparative titles and refers to already published books that are similar to your manuscript.
Comp titles are a tool used at several stages of publishing, including pitching books to bookstores, so both traditionally and self-publishing authors should find 2-5 comp titles for their manuscripts.
What makes a good comp title?
While technically any book similar to yours could be a comp title, a good comp title should meet a few specific requirements.
Comp titles generally need to have been released in the last three years. Anything older than that is out-of-date and may make you look out of touch with the current trends.
All of your comp titles should match your manuscript's audience age range. Having a picture book and an adult novel as comp titles would be inherently confusing. You look like you have no idea what kind of book you've written and who your audience is. And you've proved nothing about how successful your book could be by comparing it to these wildly different audiences.
A good comp title needs to have a strong subgenre similarity. Being a fantasy book is not enough. Does it prominently feature dragons or fairies? Is it light-hearted or grim? Is it fast-paced or introspective? To find a good comp title, you should look for books that have at least one major element that matches your story. This is best done by reading the book personally so you are fully aware of what you are comparing your book to. Looking for books that have a similar hook to your own manuscript is often going to find you the strongest comps.
Lastly, comp titles should not be household names. Comparing your book to Harry Potter is not a good look. Instead aim for more midtier success. Show that your book will appeal to a specific part of the market by choosing a book that has a reasonably favorable response from your intended audience.
If you've accomplished these four things, your comp title should be a useful part of your query or marketing tools that will help agents and book sellers quickly understand your book and who is it meant for.