I'm about to start querying my first novel and my critique group have been awesome at helping me whip my query into shape. Except they keep telling me I need to add two or three comp titles. Now, I know that this means books that are in some way like mine, but there really aren't any books that are like mine. That's why I wrote it - because I couldn't find the book I wanted to read.
In this scenario, do I still need comp titles?
Short answer, yes. You do need comp titles. Even if you don't include them in your query (which I do recommend), they are very handy if you're pitching your book at a conference, or when you get 'the call'.
Comp titles offer agents a kind of shorthand as to where your book might sit. And even if you think there is nothing like your book out there, you can still find comp titles. Think more broadly, even if it means using TV shows or movies as comps instead of books. I used to use American Pie meets The Sessions to convey the subject matter and mash-up of tones when pitching my book, Stumped.
Think outside the box a little. Maybe you have a writing style like Cormac McCarthy even thought you're writing romantic comedy. You can use that, saying something along the lines of "[my book] will appeal to those who like the visceral descriptions of violence and sparse style of Cormac McCarthy applied to the quirky characters and settings of Bridesmaids."
Now, that's a pretty silly comp, but you can get the idea. Don't get too hung up on the content of your story when looking for comps. Think about tone and style as well as characters and plot. Maybe your book is a space opera where the MC is a lesbian reincarnation of Captain Ahab from Moby Dick. Bingo! Comp title. Although generally it is better to use books published within the last five years or so...
Also think about your book's emotional resonance. If your book is a tear-jerker, use a book that made you cry as a comp title, even if the genre and style is quite different. People are often looking for something that will illicit a certain emotional response.
Comp titles can give you more space in your query for other important things because you've placed your book firmly in its place on the shelf with your comp titles. That's why they are important and why I strongly urge you to find some that work for you. Apart from anything else, you might find some amazing books you want to read!