Nailing down a thesis can be the most difficult part of a writing project whether you need it for a historical research paper, an exegetical work, or a sermon.
As you work through your resources, like class notes, readings, and preliminary computer searches, make note of the things that stand out.
Rather than write the thesis as a question, restate it as a sentence. Remember that a scholarly paper differs from a summary; it is an argument. The thesis represents the assertion that the body of the paper will support, i.e. you will prove or disprove your thesis using the evidence gathered through research. Below is one example of restating a question as a thesis:
Refine your thesis to fit the assignment. Like Goldilocks you are striving to ask a question that is neither too big, nor too little, but just right. You want something appropriate for the page limit of your assignment. For example, if you have to come up with twenty pages, consider the following:
Once you have a thesis with which to work, do not force your evidence to fit it. Listen to what the evidence tells you and allow your thesis to evolve.
This evolution can provide a nice introduction to your work. It lets you to say that based on what you knew previously, the situation appeared to be one thing, whereas in light of the evidence, it is actually something different. Then introduce your revised thesis statement and you are off to the races.