The key here is aids . They help your talk along doing what you voice cannot. Use them only to show something that would be difficult using speech alone. Photos, charts, graphs, diagrams, major points, are all good examples of using slides wisely. At first they might be hard to recognize, since there are so few out there, but you have probably come across at least a few.
Good slides stand out.
Come right to the point. They DO something. As stated above, start with an outline. Finish the whole outline, and then break it up into slides at logical points. Don't worry about color, or format or anything.