Focus on your desired outcome. What do you want your audience to think, feel and do differently as a result of your presentation? What do you want them to think about you?
Write down your key message. It should be compelling and short. Ask yourself: if you saw it as a headline, would you read on? Now imagine you're a member of the audience - would you keep listening?
More is less. Include all the content you can. It's easier to have too much and pick out the best bits than struggle for substance.
Have a clear, explicit structure - people will not listen to everything, so it will be easier for them to log back in. And give them time to digest what you say.
You are responsible for setting the mood. If in the first few minutes, your audience are looking intrigued, that is a good sign. Energy is infectious - they will soon pick it up.
It's better to be fluent than sound scripted. If you are using slides, make sure you know the links so that you can lead the flow rather than using visual aids as notes.
Remove physical barriers between you and the audience. Make eye contact with as many people as you reasonably can. The more personal it seems, the more likely people are to remember and enjoy it.
Vary your volume, pitch and tone. If you keep the same rhythm then your audience is more likely to doze off or be distracted. Silence is a powerful way of gaining attention and emphasising a point.
Show you are human. Smile at least once.
Practise, practise, practise. Whatever you say will sound different out loud to how it did in your head. If you can persuade someone to be your guinea pig, even better. Jokes, in particular, should be tested in advance.