You began gathering material from library, Internet, and field sources with a question in mind. By now, if your research has been thorough and fruitful, you know your answer. The moment has come to weave together the material you have gathered. We can vouch for two time-proven methods.
See advice on stating and using a thesis.
The Thesis Method. Decide what your research has led you to believe. Sum up what it all means in a sentence. That sentence is your thesis, the one main idea your paper will demonstrate. Then plan and draft. Include other points of view, but focus on what supports your thesis and makes it clear.
See more on research questions.
The Answer Method. You may prefer to plunge in and start writing without stating any thesis at all. If so, recall your original research question. Start writing with the purpose of answering it, lining up evidence as you go and discovering what you want to say as you write. (With this method, allow more time for revising than with the thesis method.)