Use the Blanking ‘B’ Key: Probably the handiest tip to use when presenting material via PowerPoint is the “B” key. Pressing the “B” key when presenting in PowerPoint immediately puts a black, blank slide on the screen until some other key our mouse button is pressed. This feature is more important and useful than most people realize. Note that the blanking feature of the “B” key is only available when actually in the presentation mode. You cannot use it for this effect when editing slides.
EMPHASIZE THE SPEAKER: The most important use of the “B” key is to control attention. Good presenters know that there are times that you simply want the audience to pay attention to the speaker and not look at the screen. Beginners who are enamoured with their new technology often put too much emphasis on their graphics and on their equipment and forget that these are just tools to enhance the message. Sometimes the most important thing to do is to simply turn the screen show OFF. In fact, going to a blank screen after showing some slides greatly throws the attention to the speaker. Use this when you have something particularly important to say and want the people to listen to YOU!