I think the first time I came across this tip was on Presentation Zen, or it might have been on Creating Passionate Users. I apologize for not giving credit where credit is due. Regardless, if you are a public speaker and you are not subscribed to both of these blogs, you need to be. Go do it now, I'll wait........ Good, let's start.
As part of getting ready for a large internal conference at Microsoft coming up this next week, I've been hearing my fair share of talks lately. One of the first tips I can give you presenters out there: you don't have to prove you deserve to be giving the presentation.
The time for presenting and selling yourself is in order to get the presentation in the first place. Once you have "won" the slot and are giving the presentation, you don't have to sell yourself anymore. If people show up at your talk, you have already won their attention. Now that you have their attention, KEEP IT. There is almost nothing worse than going to a talk and sitting through ten minutes of "ego stroking" at the beginning. Unfortunately, first impressions are big, and if you bore the heck out of your audience for the first 5-10 minutes of your talk, it's going to be really difficult to gain their attention back.
But you may ask: "If I don't talk about why I'm credible in the first five minutes, then how do I do it?" There is one popular saying that applies here: "The proof is in the pudding." Show your credibility on the subject by the content of your content. Now matter how credible you might be in real life, a boring or inaccurate presentation is going to spoil that.
So remember, you deserve to be there because YOU are the one giving the presentation. Forget about the five minute introduction, just dive into the core of the talk and enjoy the ride :).