Let’s imagine for a moment that you’re ill and you go to the doctor. You get into the examination room, and the doctor arrives, and before you’ve even opened your mouth, she prescribes a pill for you. What would you think?
Of course, you’d think the doctor didn’t know what she was talking about. You'd think to yourself, what a terrible doctor! We all want our doctors to listen first, talk about the problem with us, and then give us the answer.
The same holds with public speaking. Most speakers make the mistake of our hypothetical doctor. They immediately start dumping what they know on us without listening to us or talking with us about our problems.
Speakers need to establish both credibility and trust with their audiences, just like doctors. You must establish trust first, by showing the audience that you understand its problems. Then, you can demonstrate your credibility by showing that you know how to solve those problems with your expertise. If you go for credibility without trust, your relationship with that audience is doomed.
Remember the doctor. Focus on the problem first, then your solution. Trust, then credibility.