A thesis statement is a concise sentence -- usually appearing at or near the end of the introductory paragraph -- that previews the essay's topic by stating the main idea and the major points you'll use to prove it. You can check your essay to make sure that you remain focused on your central idea and that your main points are covered in the same order they appear in the thesis statement. Reverse outlining -- or making an outline of your completed essay -- can help you verify you've accomplished this.
Just as a thesis statement provides the essay's direction, a paragraph's topic sentence alerts the reader as to the subject of each paragraph. In an expository essay, the topic sentences follow the order of the thesis's main points, while the rest of the paragraph provides supporting content. For example, if your topic sentence states that recycling preserves natural resources, the rest of the paragraph should explain how it does this. To make sure you've stayed focused in each paragraph, try underlining the topic sentence, then circling key words related to its central idea.
Because an expository essay is rooted in factual information and not your own opinion, you should back up each main point with clear examples. This evidence can take the form of specific notes from your research, personal anecdotes or quotes or paraphrases from reputable sources such as scholarly journals or research studies. Your paragraph should also explain the significance of the evidence through at least a sentence or two of analysis. Santa Barbara Community College's writing center suggests considering why you chose to incorporate each example, as this can provide a clue to the information's value.
Transition sentences are important to expository writing because they show how each concept connects to the next. Each paragraph should not function as its own separate unit; readers should be able to gradually learn about the topic as the author unveils each point. One way to create transitions in your writing is by including signal phrases, like "in addition to," "however," "meanwhile" and "because of." These can help you point out comparisons and contrasts, exceptions to rules and cause and effect relationships.