Make sure you fulfilled the assignment. Reread the instructions for information about the purpose and writing style that your teacher expects. Check your paper's format, length and resources against the instructions.
Address the big picture before checking grammar and spelling. At Purdue's Online Writing Lab, they recommend that writers first make sure that the paper has a central focus, is appropriate for the intended audience, has good organization and has good idea development.
Acknowledge counterarguments. Write about the research that does not support your thesis, and then explain why your premise remains valid despite these counterarguments. This tactic allows you to demonstrate critical thinking skills and show that your argument is well thought out.
Use credible sources such as scholarly books, professional journals and websites from respected institutions such as universities. If you think one of your sources isn't up to par, find a better reference to replace it. Ask your teacher or a librarian whether a particular source is credible if you're not sure.
Review your paper's outline. After you've finished the paper, you may decide on a different organizational structure. Moving whole sections around to change how you present information can make a big improvement.
Check each paragraph and sentence for meaning. Each paragraph should relate to the paper's purpose. Each sentence within a paragraph should support the topic sentence of that paragraph. If you find extraneous information, you'll have to decide whether it supports the purpose of your paper or should be deleted.
Use the active voice rather than the passive voice. To identify the passive voice, look for a "to be" verb followed by another verb that ends in -ed. In almost all instances, you can rewrite the sentence so that it is in active voice. For example, "Height is determined by DNA" is in passive voice; "DNA determines height" is in active voice.