I have already spoken of failures in preaching by looking at the book 'Why Johnny can't preach' but here I want to draw together a few biblical principles and some practical observations about what contributes to a good sermon.
First and foremost, apart from prayer and reading carefully the text, I would say that the preacher wants to consider the passage before him in careful detail. This means taking account of the meaning of the words in the verses, what the background of the passage is and it's grammatical context. So as the preacher does his homework on the passage, he is asking if there are some things that are not clear here, or whether there is some doctrine being addressed here, and implications arising from that and so on. But what is kept in mind and this is the major point I am making here, is that in your study of the passage and preaching of it, it is not enough merely to read out the verse and assume everybody understands what is being said there. As we read in Neh 8:8 the scribes read the verses, making it clear and gave the meaning so that the people could understand what was being read.
What is then required in giving their meaning is to understand the verses in their immediate context and to the original hearers. We must not just jump to some application we think arises from the passage for us today. Indeed we must teach the people of God what the passage actually means by showing what it meant to the original hearers.
As a practical consideration here, so many Commentaries fail to clearly indicate the argument being put forward in a passage, or what the point being made is and how the surrounding context reinforces that point. Many go into great detail as to the meaning of words but fail to show how it all contribute to the point being made in the passage. I am not talking about application here but the meaning of the passage. I have found that John MacArthur's "commentaries" actually are a good example of a commentary that helps you understand the words in a verse but also how it contributes to the point being made. They are not technical commentaries I suppose, as they could be better described as expository sermons dealing in depth with the passage, but they are indeed helpful.
A second but I believe related point to this endeavour is for the preacher to "rightly divide the word of truth" as Paul says in 2 tim 2:15. some translate it "correctly handle the word of truth". Most commentators point out here that it is highlighting the important role Timothy has in teaching God's Word, yet I think Gordon Fee is probably more accurate when he puts the words in their context of standing against the false teachers who are quarreling about words. Now this does not mean that the meaning of the words of Scripture aren't important. He is not saying we must have unity at all cost so don't quarrel about words. Elsewhere Paul tells us elders are to refute error, so it cannot mean that Paul is telling Timothy just to ignore what is going on. Indeed the prior verse Paul instructs Timothy to warn them about quarreling about words. Chapter 3 is a lengthy onslaught against the false teachers and Paul lays out for all how certain people in the Church have been targeted by them. As Fee points out, Timothy is to stand against their error, but his disposition is to be markedly different to that of the false teachers. This will result in, as chapter 2 tells us, that he is not ashamed, unlike the false teachers, because he correctly handles the word of truth, and that is the kind of workman you are to be.
And being such a workman is hard work!
As Homer A Kent Jr says on this passage:
Do I achieve this? Am I good at this? I do not consider myself a great preacher, but I do put in the hard work and try to follow the above principles so that I too will not be ashamed!
"Simpson says 'it enjoins on every teacher of the Word straight forward exegesis.' There must be discernment between the various subjects taught in Scripture: salvation and service, the Jew and the church. Interpretation and application must be clearly treated. Attention must be paid to the dispensing of the word, the use of wisdom and tact.The Holy Spirit will guide God's workman, but there is latent here much need for precise and earnest labour."
Perhaps you have other points your could add to those above. Why not share them with us.