So how do you use humor in a speech? Well for starters, don't put so much pressure on yourself. You don't have to be funny. Let's face it -- most speeches and presentations are boring. But, all things being equal, if you can get people to laugh, that's a good thing, because here's the one thing we know about people laughing. They're not sleeping, and they're not focused on their cell phone. They're actually paying attention, so humor can be a good thing.
But you've got to avoid a few pitfalls, and focus on a couple of basic tips. For starters, don't start off by saying, "Well, let me tell you a funny story," because the audience is thinking, "I'll be the judge of whether it's funny or not." Just tell the story or the joke. Don't announce that it's funny.
Second of all, don't give some generic, canned joke that you're got in a Milton Berle joke book. That is not a good idea at all. Make it genuine to you. Make it real. The more you can simply talk about real experiences that happened to you, and where you're the butt of the joke, the better. That's going to be much, much, much better.
And keep in mind that the humor has to have a point. Unless you're a professional comedian, then you can just tell any joke, but if you're giving any type of a presentation, a business presentation, a presentation in school, your humor has to have a point. So make sure when someone hears the story, or hears the joke, that they instantly get the connection to what it's about.
And be quick. Think on your feet. If someone says something and you can react to it, that's often the best use of humor, rather than giving some big, canned speech.
Let it come naturally, and it will be a good time for everyone. If not, don't worry about it. Just give interesting information.