Fantasy book cover designers can create a sense of wonder and magic in their designs by incorporating elements that capture the essence of the story's fantasy world, such as fantastical creatures, enchanted landscapes, and mystical symbols. They can also use color schemes and typography that evoke a sense of enchantment and mystery. Additionally, designers can experiment with unique textures and finishes, such as foil stamping or embossing, to add tactile elements that enhance the magical feel of the cover design.