1) Print out a FRESH COPY of your paper, and get yourself a pen. Read through your paragraphs. As you read through, in the margin off to the right of each paragraph, sum up that paragraph's idea in two or three words by hand; do this for each paragraph except your intro & conclusion.
2) Go back and read through ONLY YOUR PARAGRAPH SUMMARIES. This will help you see at a glance what your paper is doing. When you've read through your summaries, look back to your thesis (if you have one). Does the material in your body paragraphs match up to what your thesis promises? If so, fine: write an intro paragraph for your paper and stick your thesis in it.
3) IF YOU DON'T YET HAVE A THESIS: read through your paragraph summaries to figure out what they all add up to--what's your paper already about? Write this idea into a sentence. Double-check that the idea in this sentence matches one of the assigned topics; if it doesn't exactly fit, tweak the phrasing until it does.
4) THEN, proofread and edit your draft: read the paper in REVERSE ORDER (last sentence on its own, next-to-last sentence on its own, etc.)-this lets you catch dumb grammar mistakes without getting caught up in what your paper is about. Circle łto be˛ verbs (is, are, was, were) to go back to later; check for missing words, wrong words, misspelling. THEN go back to your circled verbs and make them active, even if you have to change the order of the sentence parts.
5) THEN, give the whole thing a final read-through to catch errors, etc. Read it ONCE MORE, just in case. Check for page #s, citations, anything you may have missed before.