Visual Hierarchy

The easiest way to give credence to the words you write is to make them appear in a visually hierarchical format. Information appearing in a hierarchical format is more likely to be perceived as important. It provides structure and order to the information presented, giving it a sense of planned and intentional design.

Additionally, people are drawn to the information they deem most important. This is a fundamental principle of human psychology. If something appears visually larger, it is worth more weight to the reader. This is why we tend to read from the largest font size to the smallest font size.