On ‘finding’ your voice or the voice of a character in writing. This could apply to preaching and real life as well:

Though you shouldn’t consciously work on your voice as you write, there is a way to encourage it when you get to the self-editing stage. Start by rereading a  short story, scene, or chapter as if you were reading it for the first time…Whenever you come to a sentence or phrase that gives you a little jab of pleasure, that makes you say ‘Ah, yes,’ that sings – highlight that passage in a color you like, or underline it. Then go through and read aloud all  the sentences you highlighted or underlined. Don’t analyze them for the moment, just try to absorb their rhythm or fullness or simplicity or freshness or whatever made them sing to you. What you’ve been reading aloud will represent, for now, your voice at its most effective. And making yourself conscious of it in this mechanical way will strengthen it.

Now read through the same section again, and when you come to those passages that make you wince – or just leave you cold – highlight the passage in a color you dislike, or draw a wavy line under the uninspired sentences. Go back and read consecutively all the passages you didn’t like, and this time try to analyze what makes them different from the passages that sang to you. Is the writing flat? Strained? Awkward? Obvious? Pedestrian? Forced? Vague or abstract?…

If you do this exercise often enough, you will develop a sensitivity to your own voice that will gently encourage the development of the confidence and distinction that you want. And this is as true of a character voice as it is of a narrative voice…

– Browne and King, Self-Editing for Fiction Writers, pp. 178-179