If you want people to understand and remember your message you should use fewer elements. Elements includes text, images, meaningless clip art and logos. When you remove unnecessary elements from a slide, this is known as removing noise. Too many things on your slides (including too much text) can be thought of as white noise, interfering with the clarity of your message.
I appreciate that not every message can be reduced to a few simple words and an image. Some concepts are indeed quite complex and require detailed explanations, but this doesn’t mean that you need to clutter up your slides and reduce their effectiveness. You need to work twice as hard to figure out what it is you are trying to say and how you can express this simply.
One way to do this is to build your slides instead of presenting the complete idea all in one slide. You can do this using the animation tools, or if this scares you, just use what I call ‘pretend animation’. This is where you duplicate your slide and add one element. Say, for example you want to explain the relationship between three chemicals, all of which have their own unique properties. If you put all three chemicals on the slide and speak about them one by one, your audience will be jumping ahead and may feel overwhelmed, especially when you get to the part where you explain how they interact with one another. So start with just the first chemical on the slide and then add the second element to the next slide. Imagine how you would explain the concept if you were drawing it on a whiteboard and just do the same thing in your slides.
Introducing and explaining each concept with a slide build is a great way to get your message across without confusing your audience.