The document provides information on what constitutes a well-written paragraph, including its basic structure and features. It notes that a paragraph contains an introduction, body, and conclusion and should demonstrate unity, completeness, coherence, and emphasis. It also describes the four main kinds of paragraphs: expository, descriptive, narrative, and persuasive. Common mistakes to avoid are paragraphs being too short or long, lacking structure, missing a topic sentence, and having no focus.