If you think of a paragraph as a sandwich, the supporting sentences are the filling between the bread. They make up the body of the paragraph by explaining, proving, or enhancing the controlling idea in the topic sentence. The overall method of development for paragraphs depends upon the essay as a whole and the purpose of each paragraph; thus paragraphs may be developed by using examples, description, narration, comparison and contrast, definition, cause and effect, classification and division. A writer may use one method, or combine several methods.

Writers often want to know how many words a paragraph should contain, and the answer is that a paragraph should develop the idea, point, or impression completely enough to satisfy the writer and readers. Depending on their function, paragraphs can vary in length from one or two sentences, to over a page; however, in most college assignments, successfully developed paragraphs usually contain approximately one hundred to two hundred and fifty words and span one-fourth to two-thirds of a typed page. A series of short paragraphs in an academic essay can seem choppy and unfocused, whereas paragraphs that are one page or longer can tire readers. Giving readers a paragraph break on each page helps them maintain focus.

This advice does not mean, of course, that composing a paragraph of a particular number of words or sentences guarantees an effective paragraph