The first paragraph must inform the reader of the topic and any background information or a transition from the previous paragraph. You may list a claim, a belief, an arguable position or an opinion. You will develop the topic in a greater detail later in the paragraph. Readers look at the first sentence of a paragraph to see what it's about. That's why you must clearly state the subject in the beginning. The only paragraphs that will not have introductory sentences are the paragraphs that list series of events.
In the body of the paragraph, you need to discuss the topic in detail. You can use facts, analysis, supporting evidence, examples and any related information. This information has to support your claim or opinion. If it's an arguable position, you must present undeniable facts. You may list secondary claims if they are related to the topic. Secondary claims need to have supporting facts and information. You need to connect the old and new information. The reader must follow your train of thought. Make sure your paragraphs are not long. If you have a secondary claim, you may need to start a new paragraph to improve readability.
In the conclusion of the paragraph, you need to connect the information discussed in the body with the main topic of the paragraph. The conclusion may also be a transition to the topic of the next paragraph. Use transitional words or phrases, such as "also," "for example," "however," "as long as," "accordingly" or similar words to move from one topic to another. Transitional words and phrases help the reader see the connection between topics that the reader may otherwise misunderstand. The conclusion should not be longer than one or two sentences.