Graphic design best practices for online learning professionals can be summarized into four essential principles: 1) use universal design principles; 2) use typography for legibility and readability; 3) use effective image usage; and 4) use effective layout to optimize viewing.

Universal design principles are the basis of effective graphic design. They should be applied to all design projects, regardless of platform or medium. These principles include the principle of modularity, which means that all elements of a design should be able to be separated and organized into logical groups. Additionally, all design elements should be accessible and usable by all users, regardless of their level of experience or ability.

Typography is an important aspect of graphic design, and should be used to improve legibility and readability. The typeface, size, and typeface family should be chosen based on the audience and the content of the design. Additionally, type should be used to emphasize important elements of a design, and to create a sense of order and hierarchy.

Images should be used sparingly, and only when necessary. Images that are used should be effective and relevant to the content of the design. Images that are not used can lead to a cluttered and unprofessional appearance.

The layout should be used to optimize the viewing of a design. The layout of a design should be simple and easy to understand. Additionally, the layout should be designed to be flexible and adapt to different screen sizes and resolutions.