Prepare fully. Practise on colleagues beforehand to uncover problem areas, and rehearse timing. It will help build up your confidence.
How long in the limelight? Be realistic about how much you can cover in the time allotted - better to select a few key themes than to swamp your audience. A post-lunch graveyard slot will require higher energy and wit.
Don't write the whole speech out. Make bullet-pointed notes on small cards in clear writing.
Avoid death by PowerPoint. The fewer slides, the better. They should aid audience understanding, not provide you with a crutch. Ditch the clip art, keep information brief and talk to the audience, not the screen.
Cut the jargon. Acronyms, buzzwords and management speak won't make you sound clever, they'll confuse or bore your audience. Offer insightful advice and information. Fresh soundbites help.
Speak clearly and s-l-o-w-l-y. Don't be afraid of pauses. Do use hand gestures, but keep nervous tics in check and don't pace like a caged tiger.
Any questions? Get things going by planting a colleague or two in the audience, ready-primed. If asked a question you can't answer, own up and invite others to respond.