In many ways, selling your book into a shop is one of the most daunting parts of being an independent author. Bookstores see thousands of titles a year, so competition is exceptionally fierce. You need to be able to justify why your book should be included in the store, and why the bookseller should stock it over any other title.
Getting an appointment to see a buyer might be difficult, but it’s better than just turning up unannounced and starting to pitch the book. When you do get an appointment, assume it is going to be exceptionally brief. You need to be able to sell the book quickly and without too much preamble. Stick to three good reasons why the bookseller should take copies – any more than that and you’ll run out of time.
Let them know the kinds of promotions you are doing in the local area, why the book would appeal to the shop, and try not to go into too much detail about plot. If you’ve already run some pre-publication promotions – say by listing on NetGalley – show your reviews and the interest you’ve received. With luck and preparation, hopefully they’ll agree to take some copies. But if not, under no circumstances should you argue with the buyer over their decision. You never know, you might be able to convince them another time, but they certainly won’t if they remember you for all the wrong reasons.
Finally, do remember that there are many places that are not bookshops that might be interested in taking copies, if there is a good reason – local museums and gift shops can be useful for this.