Experts must give their audience reason to believe they are experts. It seems so obvious that it shouldn’t require discussion, but it is too often missed. Every time you interact with an audience, whether an audience of one or an audience of many, that interaction will include an assessment of your expertise. Your audience will be performing a mini-interview, of sorts. And as a result, their faith in you will either grow or diminish. They will either trust your expertise a little more or a little less. Expert interactions rarely end with a neutral assessment.
During those interactions, your audience will be using a simple method to test your expertise. They will be unconsciously asking themselves if the things you espouse as truth reconcile with their opinions: "Given what I know about this subject, can I believe this person?" Their assessment will always start and end from their own point of reference.
It does not matter if your audience has opinions that are right or wrong. They will always assume their starting position is correct. From there, they will attempt to reconcile your words and actions with their own position. If your position does not square with theirs, they will try to reject you rather than rejecting their own preconceived opinion.
Because your audience is always starting and ending the dialogue from their own prejudiced position, you need to quickly position your expertise inside their world. As an expert, your job is to discover where your audience lives mentally and then expand that living space to include the benefits you can provide.
To better understand your audience’s perspective, you should speak only after listening to them first. Once you do, you will have greater clarity and fluency in your thoughts and speech, and you will have more power to persuade and convince. When you artfully persuade and convince people about things they did not already know, but which align with their previous knowledge, you will be recognized by them as an expert.