Be confident - even if your presentation is perfect, presenting it with a self-demeaning attitude or comments will make your audience feel you could have done better. A presentation can never be better exceed your attitude!
Be brief - Why use more words when you could have used fewer? Avoid baroque terms that add nothing but unnecessary ornateness, like “utilize” instead of “use”. For every sentence or bullet in your presentation, constantly ask yourself “What do I really mean?” and “Can I cut even closer to the chase?”.
Make an outline before you start to create slides - This one is hard to follow! But it saves time if you can, and probably makes the presentation clearer.
WHO IS YOUR AUDIENCE? - It doesn't matter how much you prepare if you miscalculate your audience.
Practice, practice, practice - Did you think you could just create the slides and then get up there and do a killer presentation? Well, you're probably wrong. Run through your slide deck several times and do your presentation the way you plan to do it, polishing and pruning each time.
Turn the clock on - You should time your presentation every time you practice. This will tell you how likely you are to go over the given time limit. And you will go over the time limit if you don't practice with a timer!