I've had the opportunity to study the art of public reading with voiceover artist David Thomas. I've also had the amazing opportunity to have one of my stories read out loud by actor Joshua Harto in WordTheatre in Los Angeles. Seeing how the pros interpret words on a page and perform them was extremely educational.
Before the reading
Practice a lot. Read your piece over and over several times so that you have it nearly memorized. Understand the landscape of the piece: slow down and speed up according to the story's dramatic points. Practice using highs and lows in your voice to emphasize key points, multiple characters, and so that you don't sound like a robot. You don't need to do anything fancy like using accents--in fact, a lot of people are annoyed by that.
Two tricks: a) practice reading with a wine cork clenched between your teeth. You'll sound horrible while you are doing it, but it works the weakest muscles of your mouth, and if you read immediately afterwards without the cork, you'll notice that you pronounce everything much more clearly. b) practice speed reading through your piece. Get through it as fast as you can, but make sure that you hit every word and every sound.
At the reading
1. Make sure you have the attention of the audience. You made need to wait a few seconds. You can even have a drink of water in front of them so that people know that you are preparing. Often, the opening of a passage contains key details that let the audience orient themselves, so it's important that everyone gets that information.
2. Go slowly. Go slower than you think you should, especially in the beginning. Every word in the first sentence should take plenty of time--it will seem too slow to you, but not to the audience. You can speed up later to fit the mood of your piece if you need to.
3. Use the landscape that you created during practice. Don't be afraid to emote. An audience will be more engaged if they realize that you are engaged yourself. And, keep in ming that audiences are on your side. They want to see you do well because they want to be entertained. No one wants to see a bad show.
4. Don't forget to make eye contact with the audience. Or, at the very least look out toward the audience. I usually pick out three places--one on the right side, one in the center, and one on the left--that I try to look out at regularly.
5. If you're given a time limit, stick to it. Better yet, stay under the limit by a few seconds or minutes. No one likes to be thrown off schedule.
Note: If you are using a microphone, try to practice on it ahead of time. Test to see where your mouth has to be relative to the microphone. Some require you to be close while others sound better if you are further away. Figure out where you are going to put your pages, or how you're going to hold them before you start reading. Don't let the pages cover your face or block the path of air from your mouth to the microphone/audience.
I've had the opportunity to do public readings at some book fairs, and I'm happy to say they have all gone well thanks to the advanced preparation I've done. A strong reading will get people interested in your book and make them want to read more.