This document discusses the key elements of writing an effective paragraph. It defines a paragraph as a basic unit of organization in writing that develops a single central idea through a group of related sentences. An effective paragraph has unity, coherence, and adequate development. It also outlines the basic structure of an introductory topic sentence, body, and concluding sentence. Finally, it describes the main types of paragraphs including descriptive, narrative, and different types of expository paragraphs such as division/classification, illustration, cause/effect, comparison/contrast, and definition.