The most important consideration when preparing any type of chart as a visual aid is size and:

When preparing any type of chart as a visual aid, legibility is critical because the primary purpose of a chart is to communicate information clearly and effectively. If a chart is not legible, the audience may struggle to interpret the data, leading to misunderstandings or missed opportunities for learning. Factors contributing to legibility include font size, typeface, line thickness, and the contrast between text and background colors.

While other aspects like portability, colour, and location can enhance the utility of a chart, they are secondary to ensuring that the information presented is easy to read and understand. For instance, a chart may be portable and aesthetically pleasing with great color usage, but if the audience can't clearly make out the content, the visual aid fails in its primary role.