Using topic sentences and a thesis statement makes it easier for readers to follow your argument. Topic sentences are often the first sentence of each paragraph and summarize that paragraph's main idea. Your thesis statement, which sums up your paper's argument, is usually placed in the introductory paragraph. The thesis unifies the entire essay, while topic sentences unify individual paragraphs, according to Red Rocks Community College's Online Writing Center.
Effective thesis statements narrow the subject to a specific topic and state a claim that can be defended. For example, "Butler County should raise taxes to fund pollution abatement programs" is more specific and debatable than "Water pollution harms the local environment." Thesis statements sometimes list specific points that the paper will develop. For example, if the thesis statement is "The city's bus system can solve its budget crisis by cutting routes, raising fares and selling advertisements," each strategy should have its own paragraph or section. Writing your thesis statement first can make it easier to outline and draft your paper, but if you're not sure of your argument, return to your thesis after you write the first draft of your paper.
Topic sentences are declarative statements that summarize the main idea of a paragraph. Forming the main point of the paragraph into one sentence can help you write topic sentences. For example, if your paragraph discusses how the bus system can make more money by raising fares, your topic sentence might be "Raising fares will help the bus system increase revenue." If you struggle to write a topic sentence, check whether your paragraph expresses one main idea. If it doesn't, you may need to break your ideas into several paragraphs, each with its own topic sentence.
After you finish your draft, ensure that your topic sentences all relate to your thesis. If they don't, edit your thesis or body paragraphs to refocus your paper. If your paragraphs feel disconnected, use transition words such as "next" and "however" in topic sentences to link paragraphs together.