A document of a given type should have the same structure independent on when or by whom it has been written.

Navigation options should be the same throughout the documentation.

See Use Templates.

Readers expect a common structure for documents and the documentation. A requirement documents should have the same structure independent on when or by whom it has been written. Navigation options should be the same throughout the documentation.

See Standard Layout.

The documents should be written in the same tone and language complexity. Readers have an easier job to digest the information in the documentation if the individualism of different authors does not shine through.

A clear language also reduces ambiguity which may lead to false understanding.

See Employ a Style Guide and Maintain a Glossary.

Diagrams should use a notation that is properly explained. Every element within a diagram should be explained. The elements of a diagram should be limited to what is essential to a given context (7+/-2 elements per diagram as a crude rule of thumb).

The level of details revealed in a document should match the expectation of the audience. Therefore it should be made clear by the author what the level of experience the audience should have, which roles they are in and which level of details is provided. It is also important to state the purpose of the document to the audience.

With this information the audience will have the right expectation for the document.