Beginning the Writing
Some of the most important work you will do on your paper might be called "mind work." Mind work does not entail any writing (although some people like to keep their ideas recorded by jotting notes on envelopes, napkins, sales slips, etc.), and it starts as soon as you know the assignment for the paper.
You have thought about your paper for days, perhaps weeks. You have read research, talked to friends about topics, discussed your assignment in class, and made various notes to yourself about what you want to write.
Remember that the word, "argument," may be used in a different way than you might use it in daily conversation. Casually, you may use the word to mean a fight or disagreement. You may not see your thesis as a statement of disagreement or as an impetus for a fight. Nevertheless, in your paper you will present a topic and direction or claim; you also will devise a means to demonstrate to your reader that your thesis is viable. The means you devise is an argument.
Once you construct a viable thesis, develop it by writing several topic sentences to support it. At this point, do not concern yourself with whether or how the ideas of support are connected. Your goal here is to uncover every major idea you need to argue or explain to thoroughly support your thesis. (Sometimes ideas for thesis support come from your research. Review critical pieces to remember important points you wanted to discuss.) These topic sentences should represent what you believe to be the component parts of your thesis. You will create at least one topic sentence for each of the component parts. You may create a series of topic sentences that support other topic sentences.
When you have completed constructing your thesis, developing and expanding your supporting points, and designing and writing your arguments, you will be ready to write your conclusion. You may select from a number of ways to conclude your paper (for example, a summary of points, a reiteration of your thesis, a synthesis of all your arguments). Your purpose is to bring your topic to a close.
You can write your introduction last. At that point, you will know the central purpose of your paper and the fully developed direction or claims you have created. Now you can write an introduction that will set the context for the thesis your wrote and the arguments to come.