Avoid low contrast colors. For example blue on green, orange on yellow. In general, avoid using red. Keep in mind that monitor quality varies from site to site. Test color combinations at different color settings during development to ensure that all of your audience will see an effective visual.
Thin lines can appear to waiver on-camera.
If you use lines in your visuals, make sure they are at least 3 points or wider. Avoid displaying complex or dense diagrams on the document camera. If you send handouts to the viewing locations before the presentation, make sure that each handout is arranged in the order of presentation so that your audience can take notes and follow along. The best colors to wear are moderate hued blues, greens, and purples. Colors appear darker than they really are, so navy blue, for example, will look black on-camera.