1. Topic: What is the main subject you're writing about?
2. Claim: What is your specific argument or point of view about that topic?
3. Reasoning: Briefly, why do you believe your claim is true? This part can sometimes be implicit, but it's always helpful to at least hint at your supporting arguments.
Let's break it down with an example:
Topic: The effects of social media on teenagers
Claim: Social media has a negative impact on teenagers' mental health.
Reasoning: ...because it can lead to increased anxiety, depression, and body image issues.
Complete Thesis Statement: "Social media has a negative impact on teenagers' mental health because it can lead to increased anxiety, depression, and body image issues."
Remember: Your thesis statement should be clear, concise, and arguable. It should also be specific enough to guide the rest of your essay.