Don’t put a time frame
The speakers have given up their valuable time and the audience must be interested or they wouldn’t be there so why should you stop an interesting discussion just because you’ve gone over the allocated time. If anyone wants to leave you’re not stopping them so just allow the session to carry on until there’s only one person left.
Allow “questions” that aren’t
Some people will want to use the time allocated for questions to push their own agenda or tell a story specific to their own life and circumstances. Freedom of speech is important and you shouldn’t try to curtail this.
Don’t clarify the question
Some questioners may mumble, have a strong accent or be unable to use a microphone properly. They might struggle to frame the question clearly. That isn’t your problem. The rest of the audience should be paying close enough attention that they can put the answers into context by themselves.
Allow one or two people to dominate the session
If a couple of people or just one individual has a lot to say or is particularly passionate then that’s ok – it’s important to let them express themselves and the rest of the audience can always just decide to leave.
Have one “just because”
Even if the event doesn’t need or wouldn’t benefit from a Q&A session include one – interactivity is a definite “good thing”, right?
Don’t stick to your word
Things happen and the world changes. Just because you told everyone the session would last 30 minutes doesn’t mean you have to stick to it. Flexibility people!
Allow lots of people to talk at the same time
All the audience members are grown-ups and, anyway, what gives you the right to tell people what to do? If more than one conversation is happening that’s a sign of interest.
Don’t allow for follow up
Your speakers are important people and may not want to share their contact details and allow for follow up. Everyone should be able to get their question answered in the room so there’s no need to allow for follow up.