Making sure that your essay has no mistakes as it will make a big difference to how it is perceived by your reader. Carefully read your essay from start to end, looking for any grammatical, spelling, typo and punctuation errors. If possible, give your essay to a friend to proofread, since we are less likely to spot mistakes in the text we have written ourselves.
You should also ensure that you have properly formatted your references and any explanatory footnotes included in your essay. Appearances matter! Check that your essay is presented in the format stipulated by your department.