(not-entirely-relevant-image from here.)
When your book is about to be published, it’s a good time to sit down and think about how to talk about it to people who are members of the general public (if you haven’t already).
Figuring out how to talk about your book to people is a thing that can take actual time and effort. Even though you’re the writer of the book, that doesn’t mean that you’ll automatically know the best way to talk about your book without thinking about it first. And you probably want to make sure you’re okay on this front before you’re at a convention or on a panel and someone asks you what your book is about.
Just like it probably took you some time to come up with your book title, a good pitch sentence can take some effort.
‘It’s complicated,’ may be a useful relationship status, but it’s not really a phrase that convinces people to buy books.
You want to keep your pitch sentence short — one or two sentences is ideal. Why so short? If you’re talking on a panel, or to a person browsing at a show, they may not have five minutes for you to recount your whole book plot to them. They may not have one minute. You want to start off with something that gets their attention — and then gives you the opportunity to elaborate if they’re interested enough to ask for more details (or not already convinced).
Having a pitch sentence that is intriguing/tantalizing is generally a good idea, because it gets your potential readers involved and saying, ‘What next?’
Comparisons are great too! The reason why comparisons are so helpful is that you’re basically saying, ‘if you liked X, you’ll like my book.’ For this reason, you should always use something really popular and omnipresent as your X — comparing books to texts like Jane Austen’s works or The Odyssey (when they’re actually like those books) is a good general direction. And presumably, anyone coming to you to hear about your book is a fan of books; they should be able to instantly tell if they’re interested by your analogy to either Fight Club or Gone With the Wind.
When you’re comparison-ing, you should also think about your audience — if you’re at a children’s book festival, you might describe Paul Pope’s Battling Boy as ‘like Rick Riordan’s Percy Jackson series, but set on another planet,’ but that probably wouldn’t fly if you’re talking to either adults or comics readers.
Just because you’ve assembled a single-line pitch sentence for your book, that doesn’t mean it’s not complicated. Books are complicated and mysterious and wonderful and long things! What the one-sentence pitch is meant to do is to shine a flashlight through the keyhole so passers-by can get a glimpse of the wonders within — and get excited to see more.