1. Speak what needs to be said, and then be silent; there is no virtue in rambling and it is rude to your hearers.
2. Never lose sight of your goal: that Christ be formed in the hearer.
3. Begin with the readings and feed the people of God from them.
4. Honor your fathers - study how the readings have been proclaimed in the Church - this is far more helpful, interesting, and important that spending time in modern commentaries. Pride of place should be given to Luther's Postils in your reading, but don't forget that HE got much of his insight from the fathers who came before him, especially St. John Chrysostom.
5. In honoring your fathers, pay special heed to the points at which they seem to be silly; be silent before them and listen, think and ponder what they say. Their folly may be the wisdom of God.
6. A sermon that does not get the hearers to the Cross has been worthless, for the Cross is the prism from which we view all things, and is it the key to unlocking the Sacred Scriptures.
7. Pay special heed to the Jesus "proprium." That is, what do these readings give you of Jesus that they alone give?
8. If you think you understand the OT without referring it to Him who said that the Moses and the Prophets testify of Him, you have not understood it at all.
9. The pulpit is not the place for your bright ideas, it is for speaking the Words of the Lord.
10. The pulpit is not the place for being polite: do not hesitate to call sin what it is and to call people to repent.
11. Never step into the pulpit without having prayed for God to open your lips that your mouth may declare His praise.
12. By the time Sunday evening has fallen, you should already have read the pericopes for the upcoming Sunday, and you should reread them frequently during the week, to live with and truly hear the Words of God before you try to speak them.
13. If you use "you" law (and it is law at its most potent), do not neglect to find ways to indicate to the congregation that you are very much under the same condemnation.
14. Avoid "we" gospel - for the Gospel's very essence is in its "for-you-ness."
15. Forgiveness is not a "thing" and you shouldn't make it sound like it is some kind of "get out of hell free card" that you hand over; rather make sure that forgiveness comes across as God finding the way to come to your hearers in mercy and love so that His very presence does not destroy them in their sin, but destroys their sin in them.
16. Don't waste time on telling folks how to live the blessed life before you've taught them inside and out how to die the blessed death; if they know how to die in faith, living in faith is sort of a "duh."
17. Don't preach Law - Gospel - Law. Instead preach Law - Gospel - Mystical Union.
18. Remember that preaching the Gospel is not only a means of CREATING faith; but it is one of God's prime means of SUSTAINING faith.
19. You cannot remind your hearers too often that they are "people loved by God."
20. Eucharistic preaching does not mean tacking an irrelevant reference to the Eucharist to the end of your sermon; it means to summon the baptized to that the Blood that cleanses the world from sin and the Body that belongs to God enfleshed as our brother; gifts which are not distant and imaginary, but real and will be shortly be upon the altar, in the pastor's hand and in their mouths.