I'm preaching through Isaiah.
I try to preach through the Scripture (expository), usually through a book of the Bible,
and try to do a few things.
First, whatever topic the Scripture passage is dealing with, is the topic I'm on. I don't try to take a Scripture anymore and jump to a related topic. I'm just preaching what's in there. That allows me to step all over people's toes, and throw hard punches, without it really coming from ME. It's right there. I'm just repeating it. My job is to proclaim God's message as best I can, and let them deal with it between themselves and the Lord. Same as I do. And I include me in it all the time, but I also include quotes, history, video clips, you know... keep my presentation fresh.
First and a half, I try to make it guy friendly. Women will come to church anyway, but guys... well, you know. We decorate churches with pastels and lace, talk about intimate relationships with a guy named Jesus, call Jesus the "lover" of our soul, and sing about how we want to run into his arms, and let's be honest... our churches are geared for women and old folks and families... not so much geared for guys, singles, and college age people. So I consciously try to use "guy" examples like sports figures, and of course, I try to be a "guy" when I'm preaching just a bit. I like hunting so I say so etc...
Second, I try very hard to let the Scripture teach itself. Again, I try not to go off on my favorite tangents, or use a passage as a jumping off point for something else. You know, you have to explain context and history, and you have to make sure your interpretation of a passage agrees with the rest of the Bible, but... in the end, I try to keep going back to the words in the passage I'm on. I try to preach THOSE verses. This forces me to see more specific things... John for instance might include just part of a story, while Mark explains some other things, but the REASON John only included what he included, usually reveals something important.
Third, I'm not just preaching facts or theology. I'm asking God what He wants us to know in this passage. I'm asking Him to show me what truth He wants me to tell everyone else. The message always has to actually matter, and amazingly it always does.
In my experience, even though I'm preaching through a book, or planning my messages, the Spirit still uses it.
In fact, I've noticed the Spirit plans things better than me. When I plan sermons based on topics I think they need to know, it has never worked out any better than when I preached through a book of the Bible. We had some adultery type issues in the church, and I just so happened to hit that subject in the Scriptures for the next three weeks. The Spirit knew all along I needed to be in that spot in the Bible during that month.
And one more thing, in my preaching I'm trying to help people understand how I came to the conclusions I have, and how I figured out a passage, and what they can look for... in other words... I want them to be able to study the Word on their own, too.