This is often difficult as many panels never meet in advance, but in our social world many folks are online and can be found. Do Google searches on their name and the topic at hand, and you may be surprised what you find online.
Research the topic
The most entertaining panels have a dash of debate, look at an issue from many angles, practical steps to get started, and tell a few jokes. Find where the points of contention are and be sure to bring it up, this is how you’ll bill the panel. Use a blog post, Twitter or other feedback tool to glean questions from the community.
Properly market the panel
Successful panels will often have a title that is catchy, in tune for the conference, and has a detailed summary of what the audience will get out of it. You should blog about the upcoming panel, and the panelists should too.
Develop agenda bulletpoints
I try to establish some general high level bullets, 3-5 is good, so it helps the panelists to prepare and research. Don’t get into overly detailed questions, you never want them to be overly rehereased. I always have some secondary questions if no one asks questions, and it’s best to throw some curve balls to panelists after they warm up.
Have prepared notes
Print out the research you did of their bios, points of contention, the high level agenda, and follow up questions you may want to do. I’m known for requiring the panelists to bring a case study or example with measurable results.
Before you use powerpoints, really think it through
In most cases, panels should focus on the discussion and interaction between the panelists. Presentations should only be used in these situations: They add value by visualizing a conceptual concept, you’ve some industry stats that preface the event, or there’s a funny video that gets the crowd warmed up. Have a mental checklist: Is this going to add value? Does this give each panelist an equal response? Is this truly necessary?