Designs for Merch
Let’s look at what book references makes great designs for merch. I have broken them into three main types of designs:
Book Quotes: If your readers love a quote from you books, have it made into a fun design in an style that matches your book or genre.
Character Based: If your readers have a favorite character, couple, or group of friends, design merch around them or around what the group calls themselves
Ex: Team Edward or Team Jacob, Team Harry & Ginny, The Cupcake Posse, List Individual Character Names or Couple Names
Location Based: Does your book center around a school or event? Or do your characters all work somewhere? Or can you create a business or event shirt around something a favorite character likes? Have merch featuring that location.
Ex: Welcome to <location from your book>, Greetings from <book location> and feature map of location, Stars Hollow High, Hogwarts School of Witchcraft & Wizardry, <Location> Fall Fest, Hagrid's Motor Bikes, Central Perk (Friends)
Also, these ideas are just general suggestions, and ultimately designs should be customized to your books and your readers.