“Don’ go burdenin’ other people with your sins. That ain’t decent.” – John Steinbeck in The Grapes of Wrath

One of my favorite publications about presentation skills is Scott Berkun’s “Confessions of a Public Speaker.”  In his book, Scott tells about his life as a professional presenter and testifies about embarrassments and triumphs he has experienced when speaking to crowds of all sizes.

Over the past two decades, I have crafted and delivered many public and private presentations. In this article, I’d like to share some best and worst practices with you. Below is my list of the seven cardinal sins that every presenter should try to avoid. I confess that I have repeatedly committed all of them. But no speaker is perfect. Let him or her who is without sin cast the first stone…

1st sin: Too long

The former Cuban leader Fidel Castro, who is famous for delivering long-winded speeches, addressed the 1986 communist party congress in Havana for 7 hours and 10 minutes.

And still, El Comandante’s listenership may have called itself lucky because PowerPoint was only launched officially in May 1990. By extrapolating the slideware generating habits of some of my colleagues at work, I estimate that El Caballo’s oration might have been good for, say, 750 slides. As some sources claim that you need at least one hour of preparation time for each minute of presentation (which IMHO sounds a bit overdone,) this would have taken El Jefe Maximo a mere 430 hours (or almost 54 working days) of crafting. Maybe in Cuba, time isn’t (or wasn’t) money at all?

Your audience may be spending valuable time and money to attend a presentation too. Don’t waste it. No single speech should take longer than necessary.

So, how long should the ideal slideshow take?

  • There’s actually a very simple prescription for that, formulated by author and Canva evangelist Guy Kawasaki who called it the “The 10/20/30 Rule of PowerPoint”, which says that a PowerPoint presentation should have ten slides, last no more than twenty minutes, and contain no font smaller than thirty

And if the time slot that has been reserved for you happens to be longer or shorter than these mere 20 minutes, here’s another easy-to-use formula for calculating the number of visuals you can afford to put on:

  • Always begin by deducting 1/5th from your speaking time, and reserve it for interruptions, questions, and answers. Then — assuming that the average presenter spends between 2 and 3 minutes per slide — divide the remaining minutes by 2 and by 3. The results of this simple calculation will give you an upper and lower limit for the number of visuals you can comfortably run through.


2nd sin: Too much detail

Some time ago, I went shopping for a new wristwatch. Although I am working in the digital industry, for this kind of stuff I’m still pretty much into analog, and I don’t have the intention to buy a smartwatch anytime soon – at least not as long as the device’s battery life is comparable to my smartphone’s.

Trying to convince me about the superiority of his merchandise, the jeweler tried to explain me that the oscillator in a quartz clock functions as a small tuning fork, and is laser-trimmed to vibrate at 32,768 Hz. Huh?  Didn’t I enter his boutique for simply buying a new timepiece? Why did I need to know about all the internal mechanism of a watch? And was this guy really that smart that he knew all these nitty-gritty detail, or did he just try to impress, persuade or mislead me by dropping numbers and citing trivia?

Here’s some advice for the jeweler. As well as for every sales person, or anyone delivering a product presentation:

  • Not every person is interested in the nitty-gritty of your product. Keep your presentation short, sweet and to the point. Limit your content to the essential.
  • Even if you are the expert in the room, you don’t have to overload your audience with all your explicit knowledge. Don’t spread the jam by giving superfluous details!
  • Try to stay within your comfort zone. Don’t introduce topics that you hardly know anything about. If your public has a bad day, they might start asking you more difficult questions – for which you may not have a good answer ready.
  • Don’t present eeeverything you know about a single topic. As a rule of thumb, make sure that for every minute you talk, you have about three minutes of ‘backup material’ (more information, related topics, anecdotes, …) available.
  • Always be prepared for detailed questions and discussions. And if you don’t have the right answer on hand, don’t be afraid to say “I don’t know” or “let me look this up and get back to you.”
  • Know your audience. Be able to change your style, your presentation flow and your level of detail. With the right tone of voice and a good story, you will certainly convince them that you’re a person of interest, that you are an authority on the topic you present, and that you have the “right to speak” (or to sell quartz wristwatches).

3rd sin: No story

Recently, I attended a presentation given by a famous researcher. Although his research topic was very interesting and his slides were loaded with stunning facts and figures, I noticed many people in the auditorium playing with their phones and tablets. I’m also almost sure that many of them (including me) left the room with a “so what?” feeling.

As a computer scientist who started his career in R&I, I know that it’s not obvious for an engineer to present a complex research topic, and to cover the necessary technical details while keeping the undivided attention of an (often mixed) audience. This is why I have embraced (and started blogging about) the practice of storytelling.

Telling stories is a way to create a tension with the audience, get them engaged beyond the rational and make them connect emotionally and/or ethically. Stories produce mental images. They are a means to stimulate higher level thinking and let the audience come to a conclusion on their own. A good story enables individuals to make a leap in understanding complex products, services, and solutions.

Already in the 4th century B.C., the Greek philosopher Aristotle formulated his theory on the three persuasive appeals: ethos, pathos, and logos.


Since then, Aristotle’s rhetoric has become one of the foundations of public speaking and, as such, an equilibrated mix of the 3 ingredients should be considered a prerequisite for any well told story.

  • Ethos means ethical appeal. We tend to believe people whom we respect. We trust in products with a good reputation. We go to places that were recommended on Yelp or Tripadvisor
  • Pathos translates to emotion. We all like stories about the good vs. the bad. We prefer presenters that speak passionate about their topic. We (too) often make decisions motivated by love, admiration, fear or disgust.
  • Logos stands for reasoning and argumentation. We believe in what we can see and what we can touch. We want statements supported by facts and figures. If not, we keep asking for the Why, the What and the How.

If you think about it, ethos, pathos and logos are present in almost every area of our daily lives. And more than we realize, they determine how we (and our audience) experience situations, interact with people and make decisions. And, as for so many other things in life, the whole of Aristotle’s rhetoric is greater than the sum of its three parts: it’s neither about ethos OR pathos OR logos, but all about ethos AND pathos AND logos.

4th sin: No call to action

In web design, a banner, button, graphic or text often prompts a user to enter a conversion funnel. By clicking on it, he/she confirms his/her interest in the content and (on an e-commerce site) may enter into a next step towards buying a product or service.

As the primary purpose of most business presentations is to move the audience to action, you should make sure that you have similar mechanisms included in your talk.

So, never end your presentation with just a “thank you for your attention” or a Looney Tunes inspired “that’s all folks!” Dismiss all these men and women with clear directions. Tell them what you want them to remember, what they need to do, and how they can get there.

  • Leave ample time for questions. As a rule of thumb you should reserve around 20% of your time budget for Q&A and discussion. Make sure you are prepared for provocative or even weird questions from the room, and remember that a poor Q&A at the end may ruin the whole of your performance.
  • Summarize your main ideas and key points. Make sure you end in agreement with (the majority of) the audience and that they are ready for taking a next step with you.
  • Invite your listeners to engage in a next step. Always end your speech with a call to action or a call to application. Give them a bit of homework (like visiting your webpage, or reading a handout), make them agree on having a follow-up meeting (don’t forget to supply them with your contact details), or simply encourage them to use the products or apply the material you presented (such as the tips I am sharing in this post.)
  • Finish your presentation in a memorable way. Take the occasion to leave a final impression on your audience. Don’t stop cold, but try to surprise them one last time before you quit the stage.

5th sin: Unclear message

Even worse than a bad closing is when you let your audience go home with a “what has this guy been talking about for more than an hour” feeling.

The way you present may either help or hurt to make your point. Make your message(s) strong and memorable, and deliver it (them) in a catchy and captivating way.

In his MacWorld 2008 keynote, the late Steve Jobs presented the world’s thinnest notebook, the MacBook Air.  The Apple CEO introduced the new product with a photo of an envelope, told the audience that the new device was “so thin that it even fits inside one of those envelopes you see floating around the office,” and then pulled up and opened a real envelope that contained the new, ultra-thin laptop computer (watch the video on YouTube.) Sometimes there’s a thin line between a good and a great presenter. Steve Jobs has always been on the right side of it.

Finding the right pitch for your presentation often boils down to pinpointing a sticky story to tell. With the right mix of ethos, pathos and logos you can appeal to the hearts and the minds of those listening to you.

  • A good story has to be compelling, credible, concrete, clear, consistent, customized and conversational. If you remember these seven C-words, you’re already one step closer to a great pitch.
  • When defining your value proposition, never forget that value is in the perception of the beholder. Adapt your pitch to address the WIIFM (What’s In It For Me) concern(s) of your audience. And give them something in return for listening to you.
  • Building a message house is a great and simple means for defining, simplifying and structuring your messages, and to make sure your audience will remember them. When properly constructed, it is almost straightforward to transform this message house into a skeleton for your presentation.


  • A good way to validate your pitch is putting it to the elevator test. Can you ‘sell’ your message(s) in 30 seconds? Can you summarize your story on the back of a napkin? Can it be understood by your mother in law?
  • Finally, as shown in the MacBook Air example above, a strong opening can make a real difference. Most people decide within the first few seconds of a presentation whether a speaker is worth listening to. So make sure to grab the audience’s attention by surprising, intriguing, or provoking them.

6th sin: Boring slides

It’s tempting to rely upon material that others have created before you. Nothing as easy as making a slide deck by cutting and pasting slides from existing PowerPoint into yours. But there’s a consequence: 99% of these cut‘n’paste slideshows look like chameleons, that change colors, fonts and layout with every slide transition.

Look and feel do matter! If you want your audience to perceive you as a professional, then never compromise on the layout of your slides!

  • Real estate: Don’t overdo. Beware of creating slideuments. Apply the same template to all slides. Use plenty of white space. Limit the amount of bulleted slides as well as bullets per page.
  • Colors should contrast with the background. Don’t put together too many colors on one screen. Avoid using red text on a white or black background.
  • Fonts must be readable from the back of the room. Be consistent in style throughout the whole deck. Don’t mix too many typefaces. Avoid script fonts. Bold and italic are good to emphasize text, underline isn’t.
  • Images: use visuals that complement or accentuate your message instead of standard clipart or crapart, that adds no extra value (we all hate screen beans or know the man climbing a bar chart, don’t we?) Avoid mixing line art and photos.
  • Vocabulary: Consequently use the same terminology everywhere. Beware of acronyms and abbreviations. Don’t use jargon or slang.

So next time you need to build a business presentation, don’t feed the chameleons! Start well in advance and take your time to tune each slide. Don’t take existing material for granted. Be creative. Be consistent. Be professional.

7th sin: Wrong pitch

Even the most beautiful slides may be irrelevant to your listeners. It’s extremely important that you have a good understanding of who will be in the room. Doing some upfront research will certainly help you to tailor your pitch and (later) customize your presentation to your audience’s specific knowledge, beliefs, feelings, needs and expectations – and establish an emotional connection with them.

  • Make yourself familiar with Robert Cialdini’s principles of persuasion: reciprocity, liking, authority, social proof, commitment, and scarcity. These will help you to appear convincing, credible and trusty in front of your listeners.
  • Creating personas and asking questions about them like: “What is their role in the organization?”, “What does an average day in their job/life look like?”, “What do they value most?”, “How do they get motivated?”, and “What could be their most common objections to your product or service?” may be good means for tuning your content

This article is a slightly reworked compilation of posts that I published earlier on my B2B Storytelling blog (link below in profile), and a video recording of me presenting the 7 Sins is available on Campus in the Cloud