Determine the format of your thesis paper. Use the standard formatting for a thesis paper (hypothesis, review of literature, research procedure, facts and analysis, summary and conclusion), or else follow the guidelines provided with the assignment.
Decide on the aspect of world history on which you want to focus---for example, important dates in world history, the United States in world history, the role of women in world history, etc.
Research your subject thoroughly before you begin. History and reference books will provide your best sources, and you should try to find every book you can.
Take notes on your research. No matter how much you think you will remember, you need notes for specific details.
Once you have narrowed your focus and decided on an overlying hypothesis, write an outline. Make sure you know all of your main points and how they relate before you start writing.
Write a rough draft for your thesis paper. Allow enough time to do this thoroughly.
Proofread and edit your thesis. Check that you've detailed your historical facts correctly, that you've used perfect grammar and spelling and that your paper makes sense overall.