This is a great question, brother. No particular books come to my mind though I’m sure the well-read men in this forum will have many good suggestions. But this quote by John Owen (I believe) is what almost immediately came to my mind:
I think, truly, that no man preaches that sermon well to others that doth not first preach it to his own heart. He who doth not feed on, digest, and thrive by, what he prepares for his people, he may give them poison, as far as he knows; for, unless he find the power of it in his own heart, he cannot have any ground of confidence that it will have power in the heart of others. It is an easier thing to bring our heads to preach than our hearts to preach. To bring our heads to preach, is but to fill our minds and memories with some notions of truth, of our own or other men, and speak them out to give satisfaction to ourselves and others: this is very easy. But to bring our hearts to preach, is to be transformed into the power of these truths; or to find the power of them, both before, in fashioning our minds and hearts, and in delivering of them, that we may have benefit; and to be acted with zeal for God and compassion to the souls of men. A man may preach every day in the week and not have his heart engaged once. This hath lost us powerful preaching in the world, and set up, instead of it, quaint orations; for such men never seek after experience in their own hearts: and so it is come to pass, that some men’s preaching and some men’s not preaching, have lost us the power of what we call the ministry; that though there be twenty or thirty thousand in orders, yet the nations perishes for want of knowledge, and is overwhelmed in all manner of sins, and not delivered from them unto this day.
This is penetrating. Why? Because he engaged my conscience. I know exactly what he’s talking about when he talks about it being easier to bring my head to preach than my heart to preach because I’ve struggled with the temptation. And this is the genius of this quote. He exhorts us to preach to the conscience by preaching to our conscience!
The reason why most preaching books make it easier to preach to the head than to preach to the heart is because conscience is something very personal and particular, which most homiletics books aren’t going to be by nature. They’re trying to deal with a general concept of preaching but particular texts get into very specific idols of our hearts.
I heard @tbbayly in one of his sermons on Romans talk about how he would just listen to Romans over and over again while mowing the lawn. Why? So that the Word can dwell in him with power. Because it’s only when that happens that, as Owen says above, the Word can pass from us with power.
So, for whatever it’s worth, I think the key to preaching to the conscience is this: Live in the text and let the text live in you and prick your conscience to the point of you being wounded. And then out of the experience of the Spirit subsequently healing you, go forth and boldly lead (only with the Spirit’s help) your hearers into that same experience of being wounded (you have to be willing to touch and even open those wounds, that’s why you’ll need the boldness because they might kick you reflexively in response) because you yourself have experienced it and know it’s the only path to healing and life.