A paragraph is a group of related sentences which develops one main idea or one main topic. A good paragraph has five basic elements: a topic, a topic sentence, supporting sentences, unity and coherence. A topic is what the paragraph is about or what the paragraph discusses. This topic is usually expressed in a topic sentence.

Thus, a topic sentence announces what you are going to write. A good topic sentence has a focused controlling idea which limits or controls and announces the aspect of the topic you are going to write about. Supporting sentences develop what you state about your topic in the controlling idea. A focused controlling idea in the topic sentence helps you produce supporting sentences which are relevant to the controlling idea.

Supporting sentences that are all relevant with the controlling idea in the topic sentence produce a unified paragraph. A unified paragraph discusses only one main idea stated in the topic sentence, or more specifically in the controlling idea. Besides being unified, a good paragraph should also be coherent. A paragraph is coherent if the movement from one sentence to the next is logical and smooth. The following paragraph checklist help you check your paragraph to see if your paragraph is already good.