Take 1

While some consider overhead projectors more reliable, it is important to effectively manage this medium.  Unless you have extremely legible handwriting, type the overheads with a large font.  Occasionally glance at the screen to make sure the slide is placed properly.

Use the player on the left to view this video. Click YouTube logo to enlarge.

Take 2

Here the presenter uses an easy-to-read typed font, keeps his body clear of the projection, and carefully positions the slides on the projector.  He also uses a pen to point to key parts of the slide.

Use the player on the left to view this video.