Introduction
Preparation
Postcard Technique
Reducing your fears
Transparencies and handouts
Questions and answers
Be ruthless and cut out all unnecessary material but also aim to clearly define all technical terms without getting bogged down in detail.
Whatever else you do you must be honest and know what you are talking about. "Bluffing" will generally not work. It will usually be uncovered during questioning and will almost certainly insult and alienate your audience.
Prepare contingency plans and have alternatives ready for when things go wrong or take longer than expected. If you are working as part of a group than any group member should be able to give the whole presentation if someone else is sick, late or does not turn up.
It is always unwise to prepare presentations which depend entirely upon demonstrations or experiments unless you are very experienced. Check all equipment in good time and make sure that you have everything that you will need: extension leads for power supply, network leads for Internet connection etc.