Here are two common mistakes I have seen when people are using slides.
Mistake #1: You show your slide featuring graphs, bulletin points or a pie chart, and then you start talking…immediately. Now you have confused your audience: do you want them to process the information on the slide….. or listen to you? People can better focus when asked to do one thing at a time.
So, to enhance your clarity, reveal a slide. Stop talking. Since your body language can direct people as to how to behave, you may turn your head towards the slide, indicating that you would like them to look at the visual, or you can angle your body (just slightly) towards the slide.
Once you feel they have processed the information, you can then face your audience and begin the explanation.
Mistake #2: You spend more time looking at your slide than the audience. I can only think of a couple of instances when you would talk to the slide. Otherwise, resist the urge to keep looking back at the screen and concentrate on building a rapport with your audience by giving them eye contact.