I truly do hate sitting in an audience and watching a presenter linger on a slide for five to ten minutes at a time, gabbing away. If you are going to use visual aids to help grab attention and support your points, it helps to change the graphics frequently. For one thing, you should be making a single, easily understood point with each slide. Your audience should take away a clearly defined nugget of information or conclusion with each graphic.
One of the most amazing presentations I ever saw was a video of a speaker giving a live presentation in front of a room. The subject had to do with branding yourself as an individual. The presenter spoke rapidly and used a new slide every two or three seconds on average. I'd guess that he ran through 100+ slides in a five minute presentation. (I have been unable to find that video with any of my favorite search engines, so if you happen to know what I'm talking about and can shoot me the URL, I would be eternally grateful).
For a slide to be even marginally effective at that speed, you can imagine that it must use no text and show a single, easily grasped picture that encapsulates a resonant concept in a clearly identifiable image.
Admittedly, a presentation such as that one is a novelty item. In a long presentation of 30 minutes or more, keeping up that kind of energy and pace would be exhausting and draining for the audience and speaker alike. But I'd like you to think of it in the same way that fashion shows highlight trends and styles by exaggerating them in the costumes the models present. Take away the idea as something to emulate in a more practical way with your own presentations.
Step one is obviously to reduce the amount of text you are using. If you are a typical slide show creator, you go about your creative process by thinking about what you want to say to the crowd and then writing it in bullet points on your slides. I recently saw a business blog where the author wrote, "I gave a presentation this morning at an industry conference. Here are the slides I used, in case you are interested." Very commendable. I took a look at the presentation. It was written like a white paper. I could read the entire content of the talk on the slides. That is great as a leave-behind or reference for people who couldn't attend.
But I couldn't help feeling sorry for the people in the audience at that conference. There were only a couple of options for the type of experience they would have. If they were close enough to the screen to read all that dense text, then they probably read it faster than the presenter could say it out loud. Therefore, on every slide they were sitting and fidgeting, waiting for him to "turn the page" so they could continue reading at their own pace. If they were farther from the screen, they couldn't read it at all, and felt like they were missing some valuable content. They eventually had to shut down their visual information gathering and sit back, treating the presentation as an audio-only event.
Step two is to take the time to incorporate interesting and engaging visuals that give some kind of contextual support for the information you are presenting. Try to avoid PowerPoint clip art and auto shapes in favor of photographic images. Use stock photo libraries available on the web. Some are free, many charge $1 per image or less. The power of photography is much greater than that of abstractions such as cartoon figures and geometric shapes.
Step three is to pace your talk and your slides. This is where things get specialized for a webinar environment. In a live presentation you can easily slip in "quick" slides. Perhaps you'll use a brief title card to introduce a new section. Perhaps you'll use two slides in rapid succession to show a transformation or comparison of two items. For small periods of time, you can be like that adrenaline-fueled presenter I mentioned earlier. But on a webinar, you have to account for delays and differences in the amount of time it takes all audience members to receive a new slide. Some people have slower connections, or are experiencing heavy bandwidth usage on their local network. Some have older computers with slower graphics cards, or may have joined late and haven't cached the presentation locally (if that's how your webinar technology works). There is no way to know in advance how long it may take everybody to see a new slide (Some vendors are now incorporating indicators for the presenters so you can see when slides have been received, which is a fantastic presentation aid. But it doesn't help you while developing your script and your presentation.)
My rule of thumb is that no slide should be on the screen for LESS than 10-15 seconds. That means you can't write a script that says: "Some examples of popular sports include: Football (*slide*), Baseball (*slide*), Hockey (*slide*), and Curling (*slide*)..." A portion of your audience will still be looking at football while you are talking about curling. You need to change your planned presentation to have a little more to say about each of those sports, to give the slides time to catch up.
If you want to show a brief title card to keep your audience moving along with you, that's fine. But again, make sure that you have some filler planned while you show the slide. Section titles are great places to say, "Let's pause for a moment here before moving on to the next section. I'll take a sip of water while you think about that last point." It's okay to be human when presenting. Just let your audience know how you are managing the flow and why they aren't hearing you for a moment.
I gave you a minimum time per slide, so I expect that many of you are wondering what my maximum is per slide. It's not quite equivalent, since there is not a technological problem with sitting on a slide. Just a psychological one in terms of holding your audience's attention. I usually shoot for an average of 60 seconds per slide when pacing my online presentations, knowing that some will be shorter, some longer. I don't like spending more than three minutes on a single slide, and that's really pushing the limit.
By the way, this is another example of how recorded on-demand webcasts differ from live webinars. A recording plays at a set speed that is the same for all viewers. You can go back to using short-display slides, secure in the knowledge that your audience sees them as you display them. If you have the time and the opportunity, it is more effective to create shorter, faster moving presentations for on-demand playback than you use for a live interactive webinar.