The way information is presented visually can influence, to a large extent, the message as it is understood by the reader. Therefore, it is important that you use the best possible tools available to convey the precise meaning of your words. It must, however, be emphasized that visual presentation forms should aid the
reader in understanding the text, and should not distract his or her attention. For this reason, visual consistency and uniform conventions for the visual clues are a must, and the way given structural elements are highlighted should be the same throughout a document. This constraint is most easily implemented by defining
a specific command or environment for each document element that has to be treated specially and by grouping these commands and environments in a package file or in the document preamble. By using exclusively these commands, you can be sure of a consistent presentation form.