In a presentation, if people notice the graphics, then the manner of presentation has distracted attention from its content. This is fine for business, when the showman is really selling himself, but in an academic presentation, you want the audience to remember the data, not how the data are presented. For a presentation of research, fancy graphics are self-defeating. Your data will be the most memorable if you present them with slides that are as plain as possible. Here are some rules of thumb:
Use dark text on a light background. Unless there is compelling reason to do otherwise, use black on white. This will make the text maximally legible, it will be least affected by the room and equipment, and it will keep the room as bright as possible. The brighter the lecture hall, the less likely people are to fall asleep.
Avoid bright colours and light colours. Bright colours are distracting and light colours tend to disappear. This holds for charts and graphs as well as text.
- Use as few colours you can.
Decoration distracts. Eschew it. Every graphical device should serve a purpose.
Avoid cinematic effects—fades, wipes, dissolves and animations. Nothing distracts more than movement.
If you use graphical devices to emphasize text or to group objects, make them weak, just strong enough to guide the eye.
- Don't put much on a slide. Use phrases, not sentences. Short phrases.
Pick one font and stick to it, a font that is bold and compact. Gill Sans is particularly appropriate and ought to be available on any Macintosh running OS X.
A good way to draft a slide is to use a broad, felt-tipped marker on paper. Don't write any more than will fit comfortably.
Note that colours on projectors can be remarkably different from colours on your screen. If chromatic accuracy matters to you, get to the room ahead of time and calibrate the projector. If you are using a Macintosh, this is done the same way you calibrate the colour of a monitor.