If your store caters to kids, make their shopping experience a delight, please their parents and have a chance to sell even more.
Offer a service to the parents where they order the kid’s present in advance. You gift wrap it for them and hide it somewhere in the store. You also write the kids name or otherwise mark their gift wrapped package with ink only visible in UV light. When they arrive, you give the child a magic wand (UV torch), and they go through the store searching for their hidden treasure.
As a starting point for discovering new books at the store.
Create a list of books that customers can browse at your retail store to find a book they already read. For each such book list suggestions for a new book they might want to read in the following format: if you liked this book because of X you might enjoy these books…” List potential books for each identifiable quality of the book they already read.
It stands to reason that what people are currently interested in when visiting your website, might predict what shoppers would also be interested in your brick and mortar store.
Get regular alerts on specific activities that show greater interest (or actual purchasing trends if you also have a web shop) and take those into constant consideration in your retail store: arrangements of products, special ad-hoc promotions, etc.