Here is another thought from the book Leading with Confidence that I thought was appropriate for preachers.
He says on page 44 “As you convey your message, focus on communication, not content. Your content should be so familiar to you that you can forget it and instead give your utmost attention to truly connecting and communicating with your audience.”
He is not saying the “content” is not important. He is saying that you should be so well versed in the content that you are free to focus on communicating it when you stand in front of your congregation.