You're Only Joking
Humor can improve a speech better than anything else because it gets the audience to react positively to you. A joke will also help the audience remember a serious point you want to make. But this is the trickiest part of a speech, since everyone's taste is different and few speakers have mastered comic delivery. There are easy ways to lighten up a talk by borrowing the right jokes. You can also improve your own sense of humor with more effort and create some lines no one has heard before.
“A little levity will save many a speech from sinking,” observed Samuel Butler, the nineteenth-century British novelist. Applying it right at the beginning will break the ice. The audience may be uneasy about the subject you are going to address, and you can dispel the tension with laughter. They may be skeptical about your credentials, and you can make them more receptive by being likable. Or they could just be bored after a series of speeches and need to be perked up.
The opening jest does not need to be professional grade. If the audience does not know you, expectations will be low, so the first joke may get a better reaction than later attempts at humor. But you want to put the most thought into this one because any misfire will make it more likely they will tune out from that point on (which is why some speakers warn against putting humor up-front).