A good paragraph focuses on one idea and consists of several sentences all relating to this idea. The four elements necessary to a good paragraph are unity, coherence, a topic sentence and adequate development.
The topic sentence, one that states the central idea, usually occurs at the beginning of the paragraph. The subsequent sentences then develop the topic. Adequate development includes examples, illustrations and definitions that help support the central idea. A paragraph consisting of only two or three sentences typically will not contain enough development. Coherence of the paragraph is created through the use of logical and verbal bridges that help with flow and transition.