John Piper recently wrote an interesting article on the tone that we should pursue when in the pulpit. There is a lot of sound advice here, especially coming from someone who has been preaching for 31 years. Piper writes:
What tone should you aim at in preaching?
My answer is: Pursue the tone of the text. But let it be informed, not muted, by the tonal balance of Jesus and the apostles and by the gospel of grace.
Take a moment and read the entire article over at desiringgod.org.