How to Write a Main Idea Sentence. The main idea, or topic, sentence of a paragraph is the sentence that gets to the heart of the subject of that paragraph. The. The problem with sentence 1 is that it contains too many details. Topic sentences are general, and details should appear later in the paragraph. Exercise 3. Now write two or three topic sentences for each of the following topics. You should choose two or three different controlling ideas for the same topic. Disclaimer: This site does not host any of the documents displayed in the search results. Webmasters may remove links to your webpages by adjusting bing/yahoo crawler. How to Write a Topic Sentence How to Write a Good Topic Sentence. Perfecting the skill of writing topic sentences is essential to successful essay writing. A topic sentence usually comes at the. Topic Sentences. All three paragraphs start out well with a topic sentence. A topic sentence is a sentence whose main idea or claim controls the rest of the paragraph. Write a topic sentence to cover multiple paragraphs. Not every paragraph will have a topic sentence. You may write a sentence that serves as the topic sentence for. Check your topic sentences for clarity. Ideally, you should be able to scan through your thesis statement and each following topic sentence and have a good idea of. Definition. A topic sentence is a sentence, sometimes at the beginning of a paragraph, that states or suggests the main idea (or topic) of a paragraph.