As I troll the Internet looking for materials on trial practice, I'm surprised by the number of lawyers who publish their articles on their own websites. The trick is finding the links.
Anyway, here's a lengthy and insightful article titled "Voir Dire," by Edwin E. Wright, III. Mr. Wright is a Texas trial lawyer, so he refers at times to Texas law. However, the section "Conducting the Voir Dire" contains tips that would apply in any jurisdiction.