To begin a thesis statement, start by clearly defining your main argument or position on the topic. Focus on the central idea you want to convey and ensure it is specific and debatable. Begin with a strong, concise statement that reflects your research or perspective. For example, use phrases like "This paper argues that..." or "The primary objective of this study is to..." Ensure your thesis statement sets up the structure of your paper and outlines the main points you'll discuss, providing a roadmap for your readers.