When performing for a crowd, (1) tell them what you're going to do/say, (2) do/say it, (3) tell them it has been done.For a juggling or sword swallowing trick, this is probably just fine. But I've also heard people say this is what you should do with your sermons. Begin with, "My sermon is titled: _____. Today I will give you 3 reasons why ____." Next, give them your 3 reasons, clearly identifying each point, one at a time. Finally, recap all three reasons, letting them know you have done it. In other words: Tell them what you're going to tell them, tell them, then tell them what you've told them.
This method is clearly organized, but I also think it can become boring and predictable if the speaker doesn't have some good material to keep the listeners interested. I've really had to watch myself in this regard when I listen to other preachers. If you tell me what the title of your sermon is, I already think I know part of where you're going with it. If you give me point #1 and I agree with it, I tend to go ahead and shut my ears off, and often find myself reading through a biblical text or daydreaming until point #2 comes around. Depending on whether I agree or disagree with point #2, I feel free to tune in or tune out. If your audience is capable of mentally jumping ahead of you, a lot of times they will (or at least, INTJs like me will).
David Fleer once compared this approach to walking through a house, pointing out every time you encountered a wall, door, window, or stair. "This here is the living room door that we're walking through." "These here are stairs that we're going down." We don't do that in real life; we just go through the door, or walk down the stairs. It isn't necessary to always explain what you're doing because if you do it well enough, your audience will stay with you. There are certainly sermons more information-driven where clarity is imperative and this is the better approach. But much of the time, I'm convinced other approaches are more captivating.
I say all this to say that I believe there are few things more intrinsically interesting than mystery. At this point, I do not use title slides in my sermons at all. I do not introduce what I'm going to be speaking about, and I certainly don't tell them what all to expect. I don't even spend 3 or 4 minutes on the niceties of "So glad you're here today," or "Good to see so many visitors." I try to get down to business fairly quickly, and it is often my goal that for about the first ten minutes, my audience is thinking, "Where exactly is he going with all of this?" Hopefully, by the end of the lesson I have succeed and they can see how it all fit together (I do eventually try to make some clear points). But I want them fully engaged with me during the entire process.
I think there is a lot of wisdom in Fred Craddock's inductive method. Rather than giving a point and saying, "Here are a few reasons I believe it to be true," like a lawyer, it is better to work like a detective. Gather clues as if you are encountering them for the first time. Think out loud. Let them discover the reasons with you along the way, and by the time you get to making your point, they'll be wanting to help you make it, because they have discovered the same thing in the process. Fred Craddock is even bolder than I am in that he often never even states his main point, trusting the audience to reach it on their own.
If you can give people something to try and figure out, you'll hold their attention. Don't be too quick to lay all your cards on the table.