It is impossible to say how many drafts of a paper one should write, but it is almost impossible to write a good paper in one draft. Your writing style and use of grammar are important because they affect how you communicate your ideas. Present the paper as a problem to be investigated, a novel view towards an old issue, an argument based on new evidence or research, or do something else to catch the reader's attention. Paragraphs are the blocks with which your paper is built. Probably the closest one can come to defining a paragraph is to say that it is a discussion of a single idea.
Paragraphs vary in size depending on the idea under discussion.
Like the paper itself, the paragraph is best visualized in terms of a beginning, a middle, and an end. The last sentence should be the most emphatic and should sew up the argument in the paragraph. As you might suspect, the middle sentences should get you smoothly from the beginning to the end sentence. Each sentence should in some way relate to the one above and below it. The opening sentence of the first paragraph of a short paper should provide the bait to attract the reader.