It was fall 2014. I had one more talk to give before I headed home to finish a two-week run of events and  speaking engagements across the country. As I sat in the hall eating lunch with some of the attendees, one of them asked me what I was planning to speak about.

It was a simple question but what happened next revealed two powerful lessons.

First, I didn't answer. Instead I asked the people at the table what they wanted me to talk about, and I listened to what they said.

I always prepare before every talk I give. I research the audience, understand what they want to learn and adjust my talk to focus on the issues that mean the most to them. But the most powerful form of preparation any speaker can do is to listen.

Talk to the audience, listen to their needs and hear their concerns. Nothing reveals more clearly what will most engage an audience. It's the best preparation you can do.

It was good that I listened before my talk because what the people at my table told me surprised the living daylights out of me.

I talk about social media marketing, about business success, about making money with Google and about online entrepreneurship. They wanted me to talk about... photoquotes. Just photoquotes.

Photoquotes are the images with inspiring quotes that I share on social media. They're a bit of fun that people seem to like.  It was a surprising choice but I listened. And I did it. I changed my talk.

That was the second lesson. I hadn't prepared a talk on photoquotes but I had prepared a talk on social media content.  Because I knew my topic so well, it was easy to adjust a talk that I had prepared to take into account the information that my audience had told me it most wanted to know.  

The audience loved that talk. In fact, they loved it so much that I turned my photoquotes into a book. That book sold so well that I published a second one.

When you've prepared so well that you really know your stuff, you can adjust on the fly and impress any audience you meet.

Those two things that keynote speakers do before a talk--listen to the audience; know their stuff--don't just apply to speakers. They also apply to everyone who has to address an audience.

If you're making a pitch to a potential new customer or to a venture capitalist, you're not going to have too much time to grill them about their interests. But you may well have some time for a bit of small talk before you make your pitch. Use that time to ask them what they're looking for. Listen to what they tell you. And know your product and your company well enough to be able to adjust the talk you've prepared.