Lots of people like autographs, apparently to prove or imply that they were once in the same place as a famous person. If readers put you in the same category as Mickey Mantle, Marilyn Monroe or John Lennon, play along with it—no matter how much your wrist hurts. It's part of being an author.
I've never done a formal signing, but I do sell (and sometimes give) books with inscriptions. I try to write something that relates to the book and/or the recipient. For my books on telecommunications, I often write "I hope you never get a wrong number." When a humorous book goes to a doctor, I write "laughter is the best medicine." When my memoir goes to people I know nothing about, I often write "It's never too late to have a happy childhood." Long inscriptions are probably wrong if you have 200 people lined up in a bookstore, but are fine if you are sending out one or two copies with no time pressure.
Several systems have been suggested for signing ebooks. Here's one. And another.
- Find a black-ink pen that you really like to write with. It should not be such a fine point that you risk snagging on the surface of the paper and ripping it. It should not be an ink that bleeds through the page. It should allow for a smooth, fluid, comfortable motion with little pressure. Buy a box of them. (Note from Michael: I like Sarasa 0.7 and Pilot Precise V7 pens.)
- You do not need to use your real, legal signature. Devise a brief, casual signature (just your first name is usually fine, and legibility is not necessary) that you can turn out consistently and quickly while looking at the person for whom you are signing (rather than at the page). Bigger is better than smaller. Practice until it's comfortable.
- Keep your wrist straight (to prevent injury). Move your arm from your shoulder, not from your elbow (larger muscles in your upper arm than in your forearm).
- Warm up beforehand. Stand up. Do whatever stretches and rotations you would normally do to relax your neck and shoulders. Let your arms hang loosely for your shoulders and wiggle them, paying particular attention to keeping your hands loose.
- Take breaks. Stand up and shake out your arms again.
- After the session, go to your hotel room and ice your elbow and shoulder for twenty minutes before you agree to meet anyone for dinner.
- If only five people show up, ignore everything above, because it's overkill in that situation.