On pitching: it's a fine art, and a tricky one - the instinct is to tell readers what it's about, but that's often the last piece of the puzzle. The goal with pitching is to catch a reader's attention, and then to give them something to remember. These are my best tips with examples of how I used them!
1. Find your "ooh" factor: You already know what makes your book amazing, but sometimes loving something so much means you get lost in details that aren't going to mean anything to strangers. Look for details that are unique - your hook, anything that your book has that you might not find elsewhere - and will make a complete stranger say "ooh" and ask for more information.
(For my debut, my "ooh" factor was that it featured two secrets: how a girl died, and the way her toxic behaviour destroyed her friend's life. For my upcoming novel, my "ooh" factor is that a boy wakes up in a girl's body with no memories and 100 loops of the same day to find himself.)
2. "FOR FANS OF": For traditional querying, you want to find books published roughly in the last year* that operate successfully in the same sphere you think your book will be. (i.e. for YA you want YA, for adult romance you want adult romance titles, etc). For casual pitching, you can do literally whatever you want. Use movies, TV shows, games - you're aiming for vibes. It's really valuable to be able to give would-be readers context for your book from what they already know, so "If you liked X, you'll definitely like my book" is a great tool.
(*For my debut, my comps were Everything Everything by Nicola Yoon, Looking for Alaska by John Green and The Perks of Being a Wallflower by Steven Chbosky. For my upcoming novel, my comps were If I See You Again Tomorrow by Robbie Couch and Every Day by David Levithan. Clearly, some of these books are not published within the last 5 years, so you can get a little sneaky with this.)
3. Lean on tropes and themes: Used sparingly, tropes give readers even more context from other media they know and love. Themes give a broad-strokes window into what readers can expect.
(For my debut, the tropes and themes I used were "second chance romance" and "toxic friendship." For my upcoming novel, I used "time loop" "body swap" and "friends-to-friends-to-friends-to-lovers".)
4. Ask questions: Using questions prompts a tiny bit of reflection from readers, whether consciously or not. I often use "What if?" questions to wrap up a pitch.
(For my debut, the big question was "What does it mean when your best friend dies and your instinct is relief?" For my upcoming novel, the questions are "What would you do if you woke up in a body that wasn't yours with no memory of who you really are?" and "What happens when the boy you're falling in love with forgets you at the end of every day?")
I hope these tips are helpful! Happy pitching!