We've all sat through a terrible presentation - and experienced the frustration and embarrassment of watching a speaker doing a terrible job. As a speaker trainer, and as a professional speaker myself, I've distilled the most common mistakes into the following ten, with the hope that by identifying the most common mistakes we might actually prevent terrible presentations from happening in the future.

1. They arrive last minute
There is nothing worse than the speaker that turns up right at the last minute, putting the AV team under pressure, the event organizers stressed out and generally holding up proceedings. Great presenters are always respectful of their audience - and to show respect you turn up early, ready to go, to ensure there are no problems with your presentation.

2. They are totally disorganized
The only thing worse than arriving late is arriving late and disorganized. We've all seen speakers like this - they can't find what they are looking for, they have bits of paper everywhere, their presentation is disorganized and they are really hard to watch let alone listen to.

3. Their presentation lacks structure
One of the biggest complaints that I hear time and time again is that the presentation lacked any coherent structure, which in turn made it really hard to listen to and follow.

4. They have Powerpoint and they have no idea how to use it with impact
In this day and age, with so many examples of amazing visual presentations available online it's hard to believe there are still so many terrible Powerpoint presentations. I spend half my life at conferences watching bad presentations. Way too many fonts, terrible images, too many words per slide, Excel spreadsheets, font too small and so on.

5. They are overly reliant on technology
Unfortunately, as technologically advanced as we may think we are, a sure-fire fact is that internet connections at most event centers and hotels is still lousy. This means that if you are presenting and you need live internet, odds on it will be a problem - and result in the audience sitting there for 10 minutes while you and a team of AV people are apologizing incessantly about the poor internet.

6. They don't use any humor
This is tough one. Not everyone is naturally funny and I'm not suggesting that you need to be a stand up comedian. Ideally, you can laugh at yourself if you get things wrong, or share a funny story or two that is relevant to the topic or even have a slide deck that gets a laugh or two. However you do, show the audience that you have a sense of humor and you're not afraid to use it, just make sure it's appropriate for the room.

7. They stand and read their presentations from the screen
We all know those presenters who stop and read their presentation, word for word, from the screen. This is frustrating for the audience, after all, they can read. What's the point of having a presenter if all they do is read what's on the screen? The screen should be a prompt, not the main show.

8. They make simple ideas complicated
A great presenter will inspire people to take some form of action. It might simply be to think differently, it might be to make radical changes in their life or business. Those speakers who are really good at getting people to take action are those who take complicated ideas and make them simple, easy to digest and even easier to understand and put into practice.

9. They don't do their homework on their audience
This is surprisingly common. The speaker starts and from the beginning of their presentation, it becomes very clear that they have no idea who their audience is. This tends to mean that the speaker hasn't done their homework on the people in the room and it shows.

10. They don't have any passion
I don't think it matters what you may me be speaking about, if you can't deliver it with passion, you shouldn't be delivering it. Even the driest of topics can be made more engaging with a passionate presenter. Speakers who talk about the same thing a lot, or over a long period of time can lose their passion and it shows. If you aren't passionate about your topic you can't expect your audience to be passionate.

Of course, there are other mistakes that we as speakers can make, and with a little hand on heart self-review, we might admit that we are guilty of some of the mistakes I've mentioned here. And admitting our mistakes is often the first step to make sure we stop doing them.