If you were ever nervous about public speaking, you might have heard that piece of tired advice. It's bad advice. Ignore it.
Do you really want to be imagining your boss, clients or colleagues in their underwear while you are speaking? Depending on your imagination and familiarity with your audience that might make you giggle uncontrollably. Or you might become so distracted that you forget your speech.
That advice is probably based on one aspect of the fear of public speaking. That is the fear that the audience can see you naked. In this case the naked doesn't mean without clothes. The fear is that the audience can see your thoughts - especially your fears, doubts and faults. That implies that your audience is more powerful than you - that they have superhuman powers like x-ray vision and mind reading.
The reality is that no one can read your mind. If we could there would be far less miscommunication between people. The problem with communication is that we can't read minds. Instead we attempt to interpret the words, sounds and images that we observe.
Therein lies your answer. The better that you manage the words, sounds and images that your audience observes the more control you will have over your presentations results. That control starts with your perspective.
Don't picture your audience in their underwear. And don't picture them naked. That's another old snake oil remedy. Can you imagine your convulsive laughter or primal urges destroying your presentation?
That's not the way to tame the fear of public speaking or deliver an effective presentation.
Instead, picture your audience as equals. You are good at what you do and they are good at what they do. You offer value and so do they. It's not about who has or makes more money. It's not about job titles, age or corporate hierarchy. It's about you having a conversation with a room full of equals. That's one of the secrets of overcoming speech anxiety - make it feel like a conversation.
Seeing and treating people like equals is an important fundamental shift in your perspective as an effective public speaker. Don't look down or up to your audience. They aren't better than you and you aren't better than they are. You are simply taking your turn as an equal to offer your message. They can't see you naked and you don't want to imagine them that way.
Don't fear your audience. Don't see them with superhuman powers. And don't imagine them in their underwear or less. Effective public speaking is not about undressing anyone. Deliver your presentation as a conversation with a group of equals.