The document discusses composing an effective paragraph. It defines a paragraph as a group of sentences organized to discuss a topic. A paragraph has three essential parts: a topic sentence, supporting sentences, and a concluding sentence. The topic sentence presents the topic, supporting sentences elaborate on the topic with details and examples, and the concluding sentence restates the topic. Principles for effective paragraphs include unity, where all sentences focus on one central idea, and coherence, where the paragraph clearly explains and supports the topic sentence without confusion. Different patterns can be used to develop paragraphs, such as description, process, comparison/contrast, and exemplification.