Keep the presentation simple
Don't overdue the slideshow with unecessary effects and complex builds. The more experience you have with PowerPoint the more likely you will be at risk of overdoing it.
Be Passionate about the presentation
The biggest thing that separates an average presentation from a great presentation is the ability of the presenter to connect with an audience in an exciting way. Don't hold back and be confident.
Leave the lights on:
Don't turn the lights off so that the slides look better. Most of the projectors used today are bright enough to allow you to keep many of the lights on, and not have the audience sit in the dark.
10 - Is the optimal number of slides in a PowerPoint presentation because a normal human being cannot comprehend more than Ten concepts in a presentation or meeting.
20 - You should deliver your ten slides in Twenty minutes, yes you have an hour time slot but people will arrive late and have to leave early. In a perfect world you would give your presentation in twenty minutes and then have forty minutes for any interaction or Q&A.
30 - The majority of the presentations we see have a font size in the range of 12 to 16 point, then as much text as possible is jammed onto the slide. Try less text with only crucial or important points with a 30 Size Font; remember impact and the people towards the back of the room.
Move Away from the Lectern:
Now this will not work for everybody, some presenters need to stay behind the event lectern; I guess it's used as a sort of ‘shield'. The lectern can be a barrier between you and the audience, but the goal of the presentation is to connect with the audience. Removing this barrier between you and the audience can help you build a connection.
Generally a PowerPoint presentation is there to support a speech, don't rely on just Slides you will need to project your voice and ‘utilise' the microphone, this does not mean ‘shout' into the microphone though.
Post - Matthew Allely. (material sourced from A Carsen).