Carmine Gallo, presentation coach and author of the upcoming book The Presentation Secrets of Steve Jobs (McGraw-Hill, October 2009), has counseled many executives on how to give a great presentation. He's also witnessed many common\u2014yet avoidable\u2014presentation errors that people always seem to commit. \n\nHere are Gallo's top five ways that people ruin their presentations and his strategies on how to avoid making them. Above all, Gallo says, remember that the most engaging speakers have a simple secret weapon: "They practice much more than the average presenter." \n\n1. Talk Too Long\n"Nobody is as interested in you as you think they are," Gallo says. Most people listening to presentations tend to tune out after about 10 minutes, Gallo says, based on expert opinion and research in cognitive functions. So keep the presentation to less than 20 minutes. \n\n"Look at some of the great speeches over our history, John F. Kennedy's or Barack Obama's speeches, and they're able to galvanize the nation in speeches that last under 20 minutes," Gallo says. "So do you really need to two hours to get your point across?" \n\nGallo's Tip: If your presentation has to be long, break it into 10-minute chunks. "At every 10 minutes or so, try to reengage the audience with something different\u2014don't just keep showing slides," he says. Try inserting a short video clip, introduce a quick demonstration, or have another speaker get up and briefly present. "Try to find some way to break up the presentation into manageable chunks of time," he says, "so people don't get too bored." CIO.com: In the "so bad it's good" category, we honor 8 PowerPoint slides (including Bill's) that will make you say, "What were they thinking?" See: 8 PowerPoint Train Wrecks \n\n\n\n2. Kill Your Audience with Bullets\n"People who are experts in design say that bullet points are the worst way to learn and impart information," Gallo says. "Yet what is the standard template in PowerPoint? Title and bullets. The standard template makes it easy to be boring." \n\nThe term "death by PowerPoint" rings true with most people for a reason. \n\nToo many presenters stick to the PowerPoint template, Gallo says, then cram as much information into bullets as humanly possible\u2014making it exceedingly hard for people to read the slides. And then the audience gets bored. And people start checking their BlackBerrys. (To see eight of the worst PowerPoint slides ever created, see "8 PowerPoint Train Wrecks.") \n\nGallo's Tip: First off, don't bash the software; bash the person using the software, he says. Second: Don't make every slide look the same (i.e., Title, Bullets; Title, Bullets). Gallo suggests that you use images with little or no text on slides to discuss ideas or concepts, which is also a great way to engage the audience. This will also, he says, "give the audience's eyes a rest every so often." \n\n\n3. Fail to Rehearse\n"I can't tell you how many times I work with executives who spend thousands of dollars on the actual presentation\u2014in creating the presentation and on meetings to create it\u2014and then they don't even rehearse it," Gallo says. "When you prepare and rehearse the presentation\u2014out loud, over many hours and many days\u2014you'll come across as much more engaging as a speaker and effortless." \n\nGallo says he's learned (from his research and talking to people at Cisco) that CEO John Chambers, who is known for being a terrific public speaker, rehearses quite a bit. "He will go over the slides and content of slides during many, many days prior to conference," he says. "He has internalized the content, and he's very fluid and smooth. And that's because he rehearses." \n\nGallo's Tip: Practice 10 hours for every one hour of the presentation (and that doesn't include creating the text and slide notes). Practicing in front of another person or a video camera will help even more, he says. "Most of the great presenters actually rehearse much more extensively than anyone else," he says. "They don't just wing it." \n\n\n4. Read from Your Slides\n"Most presenters who are just considered average or mediocre are usually caught reading the text on their slides," Gallo says. This dreadful presentation technique ties into Gallo Rule #2. "When you place a lot of text on slides," he says, "naturally you want to read from them, so you turn your back to audience and you read from slides on the display." \n\nUnfortunately, people read from their PowerPoint slides much more than they think they do, Gallo notes. "When you read from your notes or from slides," he says, "that completely breaks the connection you have with audience." \n\nGallo's Tip: Practice your speech and know it cold, so that you can sustain eye contact with your audience while you are presenting. "Great presenters will do this: They glance at a slide just for a second to prompt them for the next piece of information," Gallo says. "And then they turn and deliver to audience. They know what's on the slide because they have practiced." \n\n\n5. Ignore Your Body Language and Vocal Delivery\n"We know through research that 93 percent of the impression you leave on somebody has little to do with content and everything to do with body language and verbal ability\u2014how you talk, sound, look and what you're wearing," Gallo says. "Only about 7 percent of the actual words or content is important." \n\nHowever, he says most presenters will spend 99 percent of their time preparing the content and slides, and very little\u2014if any\u2014on understanding and controlling their body language and how they speak and sound. \n\nGallo's Tip: Grab your digital video recorder, deliver your presentation and watch yourself, he says. Watch for these key factors: eye contact (you should be making eye contact 90 percent of the time); posture (don't slouch, stand up straight and natural, and avoid putting your hands in your pocket); voice (don't speak in a monotone voice). \n\n"You don't need an expert coach to be there to find these things," Gallo says. "You'll pick out one hundred things on your own that are annoying or maybe are some bad habits that you never knew you did." \n\n Do you Tweet? Follow me on Twitter @twailgum. Follow everything from CIO.com on Twitter @CIOonline.