Libraries are not in competition with bookstores. Enthusiastic readers frequent both and a patron who tests a new to them author at the library is likely to buy that author's books at a bookstore. Develop a relationship with your local bookstores and work with them. As library workers, we can also learn from some of the great ideas that come from indie bookstores.
One great thing I see in indie bookstores like Tombolo Books in St. Petersburg, FL and Gibson's Bookstore in Concord, NH is marketing upcoming releases with signage and an invitation to pre-order a title. They often include a blurb, a cover image, and author information. Pre-orders are an important way for a publisher to know there will be demand for an individual title.
Assuming that a patron knows as much as we do about the library is a mistake. Library workers spend hours at the library and are familiar with its services, collection, and programs. Many patrons have a particular reason they visit the library or a way they use the building, missing things that might interest them. It's our job to highlight even the most basic services to catch those patrons who are unaware or who have forgotten about them.
Either in a separate display or as part of the new bookshelf, create signage with upcoming titles and information about your request/holds list. Invite patrons to place holds either on their own or by asking staff for more information. Include QR codes to your OPAC or eBook collection as well. While it's understandable that bestsellers will need to be included, mix in some books that might be flying under the radar as well.
You will need to have a workflow to change out the upcoming releases regularly as books are published and arrive at the library. Work with your acquisitions department and selectors to be aware of which titles have been ordered for your library.
Visit indie bookstores in your neighborhood and on your travels. You will learn a lot.