After you have found a general subject and have read a general article for background, you must next decide how to write a thesis statement on the topic you have chosen. Just as the creative artist is lead to make a final statement of truth about some aspect of life by observing and selecting from the myriad details of life's experiences, so you, as a researcher, must be able to crystallize a statement of truth by observing and selecting significant details from the wealth of material you will find on your topic. This truth, stated in a simple sentence, provides you with a thesis statement. It is a statement of your opinion, a conclusion that, from what you have read, you have reason to believe can be proven, but that you are scholar enough to discard or alter later if you uncover facts that prove it invalid.
A good thesis statement never is a preconceived notion or a personal prejudice that you could prove only by distorting or ignoring facts, nor is it the statement of indisputable fact about which further investigation would reveal nothing. It must express and idea that is arguable or debatable or one that demands further explanation. Because it is an idea, it must be expressed as a full sentence, never just a phrase. Although at this point writing a thesis statement is necessarily result in a temporary draft because you have not accumulated all the available facts yet, it does provide you with an angle of vision from which you can continue your research.
It is important to limit your thesis writing as soon as possible so that, within the limits of the time in which you have to work and the projected or assigned length of the finished paper, the truth of that thesis statement can be investigated thoroughly. No factor is more often responsible for a poor research paper than is the failure to limit a thesis. It is obvious that the less area you try to cover, the more depth you can explore and the more valuable your finished paper will be. As you do your research paper, you will probably keep narrowing your thesis statement and limiting the scope of your research to express an idea that can be thoroughly and realistically handled within the space limitation of your paper.
One way to help you with writing a thesis statement is to make a very short, research paper outline listing in sentence form the main ideas that you hope to develop in order to prove your thesis. Then look to see if any one of those points might serve as thesis as itself. Continue to go through that process until you feel you have limited your thesis as much as possible. Although this thesis is necessarily a temporary one because you have not accumulated all the available facts yet, it does provide you with an angle of vision from which you can continue your research. You now know how you are going to focus on your subject and how you are going to select the material for your research. You are ready now to formulate a research paper outline.