A lot of people think that presentations are a PowerPoint "deck" that they read to a room full of semi-bored people. Technically, I guess that does meet the definition of a presentation--you are, you know, showing people something. You're just not doing it well.
A little bit of notice here: I am not the greatest PowerPoint presenter known to man or god. When in front of large groups of people my speaking voice gets higher and higher until I'm fairly certain that dogs in nearby neighborhoods are clear on what I mean when I'm talking about whatever I'm talking about, but the people in the room are making funny faces and holding their ears. I also tend to talk REALLYREALLYREALLYFAST when I'm nervous. This does not make for ease in attention span, although the rising pitch and volume of my voice does make me impossible to ignore. I strongly suspect people are waiting to see if I will actually explode, or if someone will pull me (the kettle) off the hot burner.
However. I have eyes and ears, and I've been bored out of my mind enough times to at least be able to tell you what seems to work. As noted, I have a lovely backlog of what doesn't.
That said, everyone in the room looking at the projected image on the wall can read if they've managed to get a job where you're working. There are notable exceptions (maybe you work at a literacy center), but for the most part, they can read. Reading to them about interesting stuff--say the Lord of the Rings or something--might make a difference, but most adult people don't really like to be read to anymore unless a glass of wine and a loved one is around somewhere (or they are driving to and from somewhere trapped in traffic). In those two cases, they CHOOSE the material they're being read, which is the chief difference between you and the more fun activities.
Now, you can give a crappy presentation. There are a lot of mandatory meetings in everyone's life, and no matter how bad the presentation sucks, people are going to stay for it because they have to--your meeting is required for them. Short of physically harming animals or humans (plants are fair game!) or obscenity, they'll hang in there. They're being paid for this.
However, giving a bad presentation with a trapped audience does not do well for future engagements where you need them to actually WANT to come back. For example, a mandatory meeting on the new HR software everyone has to use bores them to death, so they don't attend subsequent update trainings, and you, the support for the new HR software, get stuck with tons of people asking questions they totally could know the answer to had they'd actually come to your subsequent meetings. However, if you'd sat through the mandatory meeting, you might actually also not come to the subsequent meetings, because it was BORING.
So, my first rule of presentations is "A presentation needs to not be boring."
It does not need to wildly appeal to all audiences. You're not expecting a critic to explain that "They laughed, and they cried," and review you for all your peers (4 stars!). No standing ovations are likely. But more eyes on you (or your presentation) than cell phones or laptops is the goal.
My second rule of presentations is "Don't write everything down on the slides."
Some people will disagree with this, especially if they like to review presentations after a meeting. And when I suggest that you don't write everything down, I'm not suggesting that you fail to write important things down...such as where to find the software that the presentation is about. What I am suggesting is that you give people a reason to actually LISTEN to you, rather than just read the current slide then resume whatever they're doing on their own machines, phones, notebooks, or imagination.
So, you have three major points to hit, and explanations regarding each point. The slide should be the three points, only. You can add your notes to the notes section of the doc (or provide a separate notes section if you're not using PowerPoint) so that people have access to all the data later. But for the actual presentation, you will not fill in the space between the points, giving people a reason to actually look at you and not just the shining words on the wall in the dark room.
My third rule of presentations is "Anticipate what they are most likely to ask, and answer it before they can ask it."
This requires knowing your audience. If you are creating training materials, you'll need to remember the first questions you had, or areas where you were confused, and specifically call that out in the presentation. If you are creating a project pitch to executives, you're going to want to talk to people who work with those executives to find out what they are most interested in, so you can include it in the presentation before they ask. Seamlessly meeting the needs of your audience makes a presentation go more smoothly, but also manages the most important task of a presentation: transferring information to the people in the room who are not you.
Don't be afraid to do research. Don't be afraid to do a mock test with co-workers before you do a big presentation so you can capture good questions. Remember, presenting isn't just about a flashy deck of information, it's about a flashy deck of the RIGHT information.
My next rule of presentations is especially difficult, "Be funny, but don't be juvenile or trite."
I frequently joke about using Dilbert cartoons relentlessly in my presentations, but actually, I don't really do that (I use, what I like to call "Hyperbole"). Presentations with one cartoon on a slide by itself are sort of a warning sign to me that I will be bored of my socks ten seconds after I read the punchline, and probably two full minutes before the presenter reads it out loud.
Interspersing cartoons throughout a presentation is actually worse; people read a lot faster than you can talk, and cartoons that are universally funny are rare. On the whole, more than one brings down the quality of the entire presentation. And just one--unless specifically on target for the presentation--can be kind of trite. No one likes trite.
What I like to do is use metaphors to explain to people how the idea comes across. People understand metaphors--to a certain degree, our brains are hard wired to look at other experiences, compare them to the current experience, and derive the difference for future reviews. Metaphors add color and life to a presentation while they explain things to people in a non-patronizing way.
Metaphors are also a nice way to work in amusement without actually being juvenile or trite.
So, for example, I had to explain what a Beta Tester was. I put two guinea pig pictures at the bottom of the screen (cute and cuddly) and then I talked about Beta Testers as people willing to be guinea pigs for our software changes in exchange for getting those changes more quickly than other users. People understood that, and, as I had hoped, laughed at the picture of the cuddly animals.
Note, you should stick with as positive a metaphor (or simile) as you can during the course of a presentation. Negative metaphors can set people into the wrong mood ("And that's why viruses are just like Hitler") and you don't want them leaving your presentation feeling negatively
My final rule of presentations is, "Keep it short!"
You should be able to see white space on the slide of at least a finger when standing in the back of the room looking at it on the wall throughout the slide. Type as much as you like into your notes, but keep slides targeted and short.
Further, keep the presentation short. I like to use up half or three quarters of the time if I can manage it. For example, for an hour meeting, I'll do maybe 22 slides. Maybe. That gives time for questions at the end, questions in the middle, and any additional amusements you might want to throw into the mix (I am not opposed, for example, to spend the first 2-3 minutes of a presentation passing out fruit and candy).
Now, there are a lot of ideas of the perfect presentation out there. I'm not advising a perfect presentation. I'm just advising on one that will get the job done. Some presentations have more specific rules (must be done in 5 minutes with three slides, go!). Certainly your audience has a major impact on what goes on the slides--execs don't like the nitty gritty details as much as they like the summary charts and data.
These are the rules that I try to do my presentations by, and I've so far seen relative success when they could understand me and I wasn't actively injuring their ear drums.