If you want literary agents, publishers, and readers to care about your book or event coordinators to book you to speak at their events, you must be able to distinguish yourself from your competition.
As a writer and speaker, your job is to educate and entertain. If readers and event coordinators can find someone more qualified or experienced than you, why should they risk their money and reputations on you?
If you can't answer the question "What does a reader or audience member need and want that they can't get from any other book or speaker, and I how am I uniquely qualified to give it to them?" refine and test your idea until you can.
If you ask yourself hard questions like this, others won't have to. You'll have already overcome their objects in your pitch and presentation.