Make an Impression
Once you've mastered the basics of putting together an effective presentation, it's easy enough to get creative. Use odd fonts and interesting color schemes. Choose fancy backgrounds and apply graphical effects. In short, provided you respect the need for clear, easily read slides and make sure they don't upstage your speech, you can safely play around with them to put across particular feelings and intentions.
But even the best slideshow can be ruined by poor presentation. Learning the material is critical, and speaking to the audience, not to the projector screen, is just as important. Practice makes all the difference, if for no other reason than you learn to compress your presentation into the time allotted. Budget your time sensibly—watching a presenter zip through the last half of a slideshow because of insufficient time is a most unedifying experience, and unlikely to impress an audience.
If you're one of those people who reads slides as if they were flash cards, it's worth remembering that all the most effective and memorable speeches were made without visual aids of any kind. When Lincoln gave the Gettysburg Address, or Churchill declared that, "We shall fight on the beaches," neither used slides to underline their points. Of course, we can't all be eloquent public speakers, but we can at least make an effort to use visual aids properly, and understand that however cool the slideshow might look, it's a supplement to the presentation, and not its focus.
Figure 10: This slideshow is for a literary audience, so mixing a papery background with old fashioned, typewriter-like fonts effectively puts across the dry and dusty feel of a library or museum.