I found this quote very inspiring (once you remove the patriarchal language 🙂 ) . . .
“The aim of the preparation is clear; it is a man prepared, not a sermon prepared. The sermon must be an element in the man’s own personal readiness for the occasion of preaching. The sermon must not be thought of as doing the preacher’s job for him, or even as being the mere instrument with which he does it. The sermon at its truest and best is the man himself doing his work. The sermon is the preacher preaching—an action, not a thing. It is an act of personal expression and communication, not a deposit of previous experience and reflection. It is this fact that makes it so difficult to preach an old sermon. The sermon is an intimate personal creation belonging essentially to the moment of preaching itself. The more truly creatively and vividly he can anticipate that moment, the more intensively he can experience it in advance, the more appropriate and effective his preparation can be. He will be preparing, not a sermon, but himself; or to say it perhaps better, his preparation of a sermon will actually be a preparation of himself and his preparation of himself will be in part the preparation of a sermon.”
– from The Integrity of Preaching by John Knox