Brad has “good advice”:http://www.j-bradford-delong.net/movable_type/2005-3_archives/000485.html for students writing essays.

bq.. The typical easy-to-correct mistakes that the students who come to see me are making seem to be two:

# Nobody ever told them–or they have forgotten, or they are too stressed for time–to _revise_. They are handing in first drafts.
# Nobody ever told them that if you are going to hand in a first draft, an easy way to significantly improve it is to, when you are finished, cut the last paragraph from the paper and paste it at the beginning. Your final sum-up paragraph–written at the end, as you have by trying to write down what you think discovered what you really do think–is almost always going to make a better first paragraph than the first paragraph that you wrote.