Rodney Decker has some fine comments on preaching here. The following is just a snippet his post.
When you preach, focus attention on the text, not on what you say about the text. Always make sure that your audience knows when God is speaking and when you are speaking. Read Scripture in big chunks. Read it well. Emphasize that what you are reading is God’s Word and authoritative. I like the pattern of some preachers (I first heard it listening to D. A. Carson), who when they read the Scripture at or near the beginning of their message, says something to this effect: “This is what Scripture says: …” (And some add at the end of the text, “This is the Word of the Lord.”) The exact phrasing isn’t important, but the emphasis is good.Amen and Amen. Do read his entire post.