Practice Makes Perfect
Too often, I see PowerPoint presentations created and finished as accomplishments unto themselves. They're considered things to begin and end, and once ended, presented at the appropriate times. The thing about PowerPoint, though, is that it is no different than index cards; it is just a tool to aid a presentation. Presenting is a very organic thing, and it's up to you. Once you have completed the last slide, it's time to practice your presentation. It's not just about practicing the timing of your presentation, but you must practice with an eye toward improvement. Make all the changes necessary to improve your presentation, and then, once you finally have it the way you want it, you're ready to impress.
Consolidate your Slides
The thing to keep in mind when creating a PowerPoint presentation is that they're best when they're minimalist. There are, of course, exceptions. "Minimal" is a relative term depending on the topic about which you're presenting, but try to keep your number of slides to a minimum in an effort to make the presentation less taxing on your audience. The more they have to keep up with slides, the less they're listening to you.
Reduce your Text
Paragraphs are great -- in novels and essays. In PowerPoint presentations, however, they accomplish exactly the opposite of your intent. A good general rule to follow when constructing your slides is that there exists a direct inverse relationship between the number of words used per slide and the slide's effectiveness. Further, a lot of text on your slides leads to the next issue.
Speak to your Audience
One of my biggest pet peeves is sitting through a boring presentation. An even bigger pet peeve, however, is watching someone give a boring presentation to the presentation itself. Public speaking can be intimidating, so when you practice your presentation, don't look at your computer screen. Since you have already committed to consolidating your slides where possible and reducing your text, the point of each slide should be fairly easy for you to remember at a glance. Therefore, glance at your slide, remind yourself what it is about, and then present the slide looking elsewhere or with your eyes closed. Anything to keep yourself out of the bad habit of presenting to your presentation.
It's Not a PowerPoint Demo
PowerPoint is, well, powerful. You can do any number of things, present information in any number of ways. The thing is, we already know that. We've been using it for 20 years and have seen much of what it can do. It is installed on the vast majority of computers sold. I say all that to say this: PowerPoint does not need your help. The presentation is not about showing how adept you are at using software; it's about relaying information. Try not to get bogged down in what you can do with PowerPoint; start considering what PowerPoint can do for you.
You Speak, PowerPoint Doesn't
This should be short and sweet. If you are thinking about adding sounds to your presentation in the form of whooshes and whirs as text swoops in from the right or left… don't. That is all.
Just Say No to PowerPoint Images
Speaking of things to steer clear of in order to create an effective presentation, let's talk about images. PowerPoint comes with clip art. This is clip art that your audience has seen dozens of times, and it does not do what you want it to do. It doesn't help relay your information. In fact, the only information PowerPoint images relay is that you did not spend enough time on your presentation. If you cannot find images online (and there are plenty of places to do so risk-free) that adequately do the job, consider taking some of your own. Whatever you do, if you're offered PowerPoint images, just say no.
Interact with your Audience
A troubling development has occurred in the last decade in the world of presentations. There is a new style of presentation, made particularly popular during the early days of the iPhone, wherein someone stands on a great big empty stage, in front of a great, oversized screen, and talks to their audience. It's a striking visual to be sure, but there's something missing… the audience. They could be entirely absent and the presentation would be unchanged. This is a problem. Not every presentation would benefit from this, but consider opening up with a question, or gathering some of the experiences of your audience and weaving it into the presentation. It might be scary, but it also might be the best thing that could happen to your presentation.
Have a Backup Plan
Computers are great, but they can also ruin a perfectly good presentation. If you've created a presentation on a PC, you might be asked to use a Mac. If you created it on a Mac, you might be using Linux (unlikely, but trust me, possible) and this can mess with your presentation in ways you might not be able to foresee. The projector might fail. The computer might freeze. If this happens, what will you do? Make sure you bring handouts of your presentation. Know it backward and forward. When life hands you lemons…
Humor is more intimidating than lecturing. At least it is to me. A joke that falls on deaf ears can stay with you more than a boring one. However, fear is only life's way of telling us something is worth doing, right? Find a funny image and put it on a slide. It can do a lot, from proving your point to getting people's attention. Nothing gets peoples' eyes up from their phones like thinking they're missing something good.
It's Not About You
If you've been invited to speak, whether it's at a meeting or a conference, it's because you have information worth hearing. In most cases, it's not because you wear a suit well or are a fantastic comedian. Remember when presenting that there's a difference between being charismatic and being egotistical. When reviewing your presentation, go through your slides and count up the instances you refer to yourself. I personally remove the vast majority. Anything I think was not created to better the professional lives of my audience, I remove.