Research your topic. Reading about your topic can help narrow your focus and find adequate source material to back up your thesis. If you don't have a specific topic in mind, preliminary research can help you refine an area of interest for your paper.
Take notes as you read about your topic. Look for common themes among the sources you are reading or questions that the sources leave unanswered.
Create a list of questions that you could answer through your research. Possible questions could include how the topic fits into a larger context, such as history or society; "what if" questions; questions that agree or disagree with a source; or speculative questions. You could also turn a positive question into a negative one, explaining why something is not significant as part of the greater whole.
Evaluate the answers to your questions. If your question can be answered too easily, you cannot find adequate sources to back it up or the question cannot be plausibly proved or disproved, it is not an adequate question to serve as the basis of your thesis.
Create a working hypothesis that answers one or more of your questions. Your working hypothesis is not necessarily your thesis, although it could be. The hypothesis guides your research and provides a framework for answering the question. When you believe you have enough solid evidence to support the working hypothesis, then you can create a solid thesis.
Craft your thesis statement. A thesis statement is one sentence that clearly and succinctly states your claim and why you believe the claim to be true.