So many times I watch presenters point to their PowerPoint slides while facing the screen with their BACK TO THE AUDIENCE. Please STOP. When you lose the connection with your audience.
Now, this may sound like a little thing but if you add reading the slides to the audience you could be facing those slides for a while. So, try pointing to the slide then turn to face the audience and discuss the point you want to make on your PowerPoint.
It takes some practice but you will see the difference.