Dont know what to do!!! Watch
Two other tips: plan, so that there is a clear structure. You can even explain this at the start - "First I'm going to talk to you about how I got started, and then about my greatest successes..."; use a powerpoint, show short video clips or bring in relevant items, but don't put lots of text on the screen. There's nothing more annoying than someone reading their speech off a screen that the audience have already read themselves.
(1) opening - uses interesting quote. explains how why they disagree with this.
(2) story about their experience of why they disagree. Good factual information and statistics used.
(3) suggests counter-argument. Exposes why this is incorrect. Quotes recent study showing it is incorrect. Makes joke.
(4) sets out why their view is important to the UK and why we should pay attention. Explains health benefits if we do pay attention.
(5) Lists shocking facts - what will happen if we ignore their findings.
(6) sums up their key arguments again, leaves us with an interesting question to ponder.
If you write down for each talk some of the techniques that the speaker uses, it will help you to structure your own presentation. Good luck.