Just trying to preach better is not enough. “Better” must be defined in some way so that it can be practiced deliberately. Ben Franklin famously improved his prose not by writing but by deliberate practice of his writing. Preachers could use his method to improve both writing and delivery. Start by selecting a superior example of preaching that you would like to emulate. Take notes of its various points and save them for later. Once you have forgotten most of the sermon, use your notes to write a sermon making the same points. Then compare your sermon with the original. This comparison step is the key to improvement, as all deliberate practice entails three continuous steps: plan, do, reflect. To practice sermon structure, mix up your notes so that they are out of order. The same process can be used for non-manuscript sermon preparation by using and comparing audio/video recordings.
Geoff Colvin, Talent Is Overrated, 111.