Honestly, things at the signing went so well, I feel uncomfortable calling this list "Don'ts". But there are a few things I would have done differently, or additionally. And you can bet I'll be doing them next time:
Take five minutes to freshen up before the crowd arrives.
In my defense, people started arriving at 1:15, and the signing started at 2. There wasn't really time for a touchup. But I was acutely aware that my hair needed a last-minute fix, that my lipgloss had slid off early on, and that a little pressed powder would have gone a long way. The thing is, no one would have been offended if I'd run to the restroom and put myself together before the official start. It was my own nervousness -- I must be here and entertaining the entire time -- that tripped me up. Next time, at the 1:15 mark, I'll excuse myself, fluff up a bit, and return feeling a little less frazzled.
Have a bottled water and mints nearby.
Smiling and chatting for 2+ hours is thirsty work. To avoid cottonmouth, have a bottle of water -- with a lid, just in case -- close at hand. The mints are a nice touch, and I did have some, but I had to dig in my purse for them. Put them close at hand so you don't interrupt the flow of the signing.
I use silver Shar pies, which look great and are less likely to give you a contact high during prolonged use. But they tend to dry out more quickly than the standard black Sharpie, and mine died halfway through. Happily, the staff had some extras, but if I could do it over, I would have tucked a few more into my bag.
Think about displays.
My cover flat for BOUND was exactly that -- laid flat on the table. It would have made a bigger impact if I'd propped it on a stand and wrote "On sale June 26 -- preorder now!" on a little sign underneath. Similarly, I would have had a stand to hold my speaker brochures, just to give them a little added oomph. Anything vertical is easier for passers-by to spot on the table.
Memorize this saying:
"I'm so sorry, we sold out of that book. But if you ask at the service desk, they'll order it, and I'll be sure to personalize it when it comes in."
This is a much more gracious thing to say than, "Oh, you can get it online." People came to your SIGNING. They wanted a book SIGNED by the author. Give them a reason to come back, and let them see you're willing to make an effort for them. Only good can come of this. Of course, you do have to hold up your end of the bargain -- be sure you're able to go back and sign the new copies.
See? Nothing earth-shattering. Nothing make-or-break. Just little things that would have made my event flow even more smoothly. Feel free to take (or leave) any of these suggestions, and let me know how your own signings go.