A excellent paragraph should have sentences that are pertinent to the paragraph's core subject and message. While the topic phrase introduces the primary concept, the following sentences add information that support or explain it. They include details about the topic, examples of how it applies to people, and other facts or opinions related to but not essential for understanding the main idea. The first sentence of a paragraph often contains a brief summary of the paragraph's content while the last sentence usually offers a conclusion or reflection on the topic. A good ending sentence helps the reader understand the main idea of the essay and provides him/her with a clear image of what will follow after the break. Other aspects that can influence the quality of your writing are grammar, punctuation, and style. The most important thing is to be aware of them and try to improve any aspect that needs it. For example, in academic essays, only the main idea of the text is considered relevant; anything else is irrelevant noise. These other things may include definitions, comparisons, causes and effects, guidelines, histories, literature reviews, methods, conclusions, suggestions, and so on. All such material is secondary to the main idea of the essay. When writing an essay, it is useful to think about what is relevant to the paper's topic.