Give me a nervous public speaker any day. Is that you? I bet you’ve spent ages writing and rehearsing your speech. You have got the timing, emphasis and pauses just right; all you could do without now is the nervousness. Try and relax a bit (such terrible advice – as if you’re not), but don’t worry about a bit of nerves – they really do give you the edge and, as I have already said, your audience wants your speech to be a success.
In contrast to you is the poorly prepared speaker who tries to cover this with over confidence. The audience will see right through this and feel cheated and unsympathetic. If they have taken the trouble to come and listen to the speaker, they justifiably expect some effort to have been put in beforehand.