Have a Story to tell
We had grown up listening to stories in different forms, fairy tails, history, folk lore, legends etc. So the human mind is trained to easily remember when conveyed as a story. Usually great presenters arrange the facts into a story and then present it.
When a presentation is due, the biggest task at hand is to come up with the story to tell. Usually when given time the story brews well, what I mean by "giving time" is the time tothink about it and let your subconscious mind to do some work before you sit down to do a mind map or a listing of the objectives and the facts to be conveyed.
Starting from Dale Carnegie's Art of Public speaking, written in the early 19th century, to Presentation Secrets of Steve Jobs , written during the last few years, list "Practicing" as the secret success factor for any presentation. You cannot replace the time spent on practicing with any other factor. Although for the audience great presentations just happens by itself, in reality the presenters make it happen by the sheer amount of preparation and practice they do. Practicing is different from memorizing, when practiced, you would know the content, you would know the flow, you would have planned when to crack a certain joke and what are the punch lines, but you wouldn't know each word you would say, if you repeat the presentation again it again you would explain using a different set of words.
Best way to practice is to imagine that you have your audience in front, hit the record button on the computer and do the presentation. Finish it and then play and see how it sounds. 9 out of 10 times you wouldn't have thought that you sound so bad during presentation, but don't worry it was just that your expectation and delivery didn't match, but with practice you can match them.
On the day of the presentation
If you think a shirt is too baggy, or if you think that a particular jeans is too flashy don't wear it. If you wear it with reluctance in mind, during the whole session part of your mind will be thinking about, how to cover it up. So the trick is to be dressed in what you are most comfortable with.
On the day of the presentation, arrive early, make sure you check the equipment (if any) like projector, mic, etc are working and compatible with your presentation. Also remember that its a cardinal sin to turn up late for a presentation, its a nightmare to go in late and having to make an apology right at the start of the presentation.
Every presenter will go through a tensed time before starting the presentation, its a very natural human thing to feel the butterflies in the stomach irrespective of the number of times you had presented before. Take a deep breath and if your hands are trembling hide it by clasping them together and if you are presenting to total strangers, look above the eye level of the people in the audience and start your first words. Then move your eye down when you feel comfortable to make eye contact by finding "your friend" in the audience.
Show alot of passion on the topic you are speaking about. Remember if you are 100% passionate about what you are presenting you might be able to transfer 10% of the excitement on the listeners, importantly the more passionate or enthusiastic you are, the more you can rub on the audience.
Click here to read by earlier post about how to manage the inactive listeners when you present.