At the Insurance Defense Blog, Dave Stratton has collected a number of litigation-related tips from David Boies.
Stratton's post is titled "Trial Practice Tips Courtesy of David Boies," and pulls quotes from the (fairly) recent Boies book, "Courting Justice: A Lawyer's Casebook, from NY Yankees v. Major League Baseball to Bush v. Gore."
As a leadoff witness you need someone who will point some points on the board and do no damage; you do not want to take a risk. If your first impression with a judge or jury is not good, your case is in trouble. You also want a witness who can explain the overall case and put matters in context.
For more, see Stratton's blog post.