Who would be reading this paper, should it be published? Although you want to write for your professor or other superior, it is important that the tone and focus of your paper reflect the audience who will be reading it. If you’re writing for academic peers, then the information you include should reflect the information you already know; you don’t need to explain basic ideas or theories. On the other hand, if you are writing for an audience who doesn’t know much about your subject, it will be important to include explanations and examples of more fundamental ideas and theories related to your research.
If you are struggling to come up with a topic that feels “just right,” ask your professor or coworkers/classmates for advice. They will likely have great ideas that, even if they aren’t options for you to choose, can inspire you with new ideas. Asking a professor for help may seem frightening, but if they are worth anything as a professor, they want you to be successful with your work, and will do what they can to make that happen.
To draw a parallel, a lawyer researches and reads about many cases and uses them to support their own case. A scientist reads many case studies to support an idea about a scientific principle. In the same way, a history student writing about the Vietnam War might read newspaper articles and books and interview veterans to develop and/or confirm a viewpoint and support it with evidence.
An easy way to develop your thesis is to make it into a question that your essay will answer. What is the primary question or hypothesis that you are going to go about proving in your paper? For example, your thesis question might be “how does cultural acceptance change the success of treatment for mental illness?” This can then determine what your thesis is - whatever your answer to the question is, is your thesis statement.