Introduction--1 page (12-page paper)  or 1.5 pages (15-page paper) maximum

This sets the stage for your reader; describes the parameters of the subject (first paragraph) and topic of the paper. Think of the introduction as poking him in the shoulder, getting his attention and beginning your story. He's going to need to know where you're going to be looking, what particular piece of the "landscape" he should be focussed on and what's significant about it. You must also tell him how to see it.

A student of mine once wrote a paper on the Whitehorse sewage treatment plant. In her introduction she told me all about the plant but didn't tell me whether her perspective was that the thing was a marvel of superior technology or an environmental disaster. Not knowing which she intended meant I didn't follow her discussion until very near the end.

The moral is don't withold anything from your reader. In your thesis statement (usually located in the second paragraph), be sure to tell him what the paper is about, what the question is, what your answer to your question is, and the three or four reasons why--briefly (in no more than two or three sentences). The detailed version of the reasons, the discussion, comes in the body. Since it's the road map to your paper, you might find it easier to write it after you've finished the rest your paper.

Think carefully about the title of your paper. It should hint what exactly your position is, point to the subject or topic of the paper and even some of the limiting factors you've placed on your work.

The first paragraph tidies up, summarizes, the argument you've made; don't introduce any new material here. In your second, final, paragraph, you can now address your reader as a more educated person. She's read the paper, followed your train of thought and so knows what you think. You're both on the same level now. So tell her what to make of these new ideas you've given her. You can also use the conclusion to speculate on the usefulness of the new knowledge for other purposes. Try to ensure your last sentence makes some kind of reference to your title for a nice ring of closure.

The body presents the detailed version of the reasons, which you mentioned in your introduction, you have for your answer to your question, also often referred to as the discussion. In each of the points sections you will need to introduce, support and conclude your discussion. (See how the threes keep recurring?) So, in each of these sections of 6-8 paragraphs, devote about a paragraph each to the introduction and the conclusion and the rest to the supporting materials, your narrative and illustrative quotes and the like.

Note that each paragraph has the same kind of structural elements as your paper: a lead or key statement, development of the idea and any quoted or cited material, and a conclusion or statement linking to the next paragraph. This means, in general, that if you end your paragraph with a quote, you've not provided some kind of summary of the point of the quote or a concluding or linking statement. Sentences, too, generally--but not always--have a tripartite structure. You can see more about threes in paper writing in "Threes in Essays, Paragraphs, and Sentences."