After spending over a year on the marketing trail, I can talk about book signings with a modicum of authority. The best signings I've had have been the result of pro-active relationship between the store and the author.
Unless you're a big name author, the signing event in and of itself won't draw many people. However, the bookstore can help promote the event by setting up a display announcing the upcoming signing. One recent CRM made a poster of my bookcover and mounted it at the parking lot and mall entrance to her store.
For this same event, I sent out a press release to the local paper 3 weeks prior to the event, complete with a photo of myself with a rescued horse. The paper ran the story a week before the signing. I also mailed out 60 postcards to acquaintances in the area. These same people had already been notified of the signing in my quarterly newsletter the month before.
At the signing, be prepared to tell what your book is about in a single sentence. (Example: This book is about a horse rescuer who helps a friend's son thwart a corporate takeover, only to attract the attention of his enemy.) Then, and this is the most important part, check out the person who asked. Are his/her eyes glazing over? Do they seem interested? If so, definitely expand. (My heroine Hope wears her heart on her sleeve. Devlin, my hero, hides his heart beneath layers of work. Their mutual enemy is determined to destroy all Hope and Devlin have worked for.) At this point, definitely stop and wait for the person to say something. Most likely they will continue to express interest or they will walk away. I offer a bookmark to everyone who stops by, even if they don't buy a book.
The hard sell - don't do it. If you have to work real hard to convince someone to buy your book, you aren't doing yourself any favors. Chances are high that this person won't read the book, will be upset because he/she had to buy the book to get away from you, or he/she will post something negative about you online.
Booksignings are big opportunities. I love talking to readers and fans. It's Christmas-morning special to have repeat customers, folks who bought your first book and and are very excited to have the next one.
Also, be on your best behavior in the store. Look professional, act in a courteous manner, respect the store employees - these are all things that will get you invited back for your next signing.
Best of luck to all with their signings!
HOUSE OF LIES, a double finalist, National Readers Choice Awards