A paragraph is a number of related sentences focused on one topic. It forms a part of a larger piece of writing such as a composition. The first sentence of each paragraph starts on a new line dented from the left.
The length of a paragraph varies. A paragraph with a length of five sentences is normally sufficient to expand on an idea. Anything more than this may be better organized into a separate paragraph. This ensures not more than one idea is covered in one paragraph. After all, the purpose of paragraphs is to separate ideas. A new paragraph means a new idea is being talked about.
A paragraph starts off with a topic sentence. This first sentence introduces the main idea of the paragraph. The sentences that follow the topic sentence discuss the idea. Some of the things the writer does here to expand on the idea include establishing the facts, providing details, and quoting examples. They must strictly be about the idea and not deviate to something else.
The last sentence in a paragraph is the concluding sentence of the paragraph. Use different words to restate the idea as introduced by the topic sentence in this concluding sentence – a summary of what has been discussed.