There are many do's and don'ts of using Powerpoint Presentations. Make sure to spell check your work, if a word has a red line under it, go back and check it again. Do not over use bullets, only mark important information, or "key points" with bullets, every single word should not have a bullet beside it. Make sure that you don't pick clashing colors on your slides, for example two different tones of the color yellow, this will be very difficult for people to see. Only put one key point of information on each slide, you don't want to put too much information on a slide and bombard a person with information.
Only give about three or four reasons supporting your arguement, after that people will lose interest in what you are saying. Make sure that you know what you are talking about, and be interested in what you are going to talk about, no one is going to be interested in listening to you if you aren't having a good time talking about your subject. Lastly, don't use the Powerpoint as a teleprompter, and read it word for word, the people you are presenting to can read the slides faster than you can speak, and will get bored. You should have other notes to complement the slides you are using.