Whenever you’re due to speak at an event take the opportunity to listen to the other speakers. There are two reasons to do this; the first is by listening to other speakers you may discover that they actually cover the same points as you’re planning to cover in your speech.
If that happens you have two choices: you can change the points in your speech that are the same as the other speaker. Or you can keep the points, but acknowledge in your speech that the other speaker has covered those points already. The examples that you give won’t be the same, so it doesn’t completely matter as long as you acknowledge it because your audience will know.
The other reason to listen to the other speakers is that they may make a point or a joke which you don’t make. Then you can find a way to incorporate their point or joke into your speech. You will get a great response from the audience because you would have illustrated that you’ve been paying attention to other speakers and you’ve also reminded them of the other speaker. It also shows that you’re secure in your speech enough to be able to reference someone else.
If it’s a laugh you’re repeating make sure that it ties in with the speech that you’re giving. You should make sure that you give credit if you can. You’re going to get a laugh because the audience will remember that they laughed before and also be impressed that you were able to incorporate the line into your speech without missing a beat.
If you go to Toastmasters, you can practice this in Table Topics paying attention to the speakers that go before you.