Insure that your responses to questions and your essays are grammatically correct. Check your spelling some even fail to run the spell check function of their word processor. If you don't have this function, ask a friend or family member to proofread for you. Keep one main thought per paragraph . Keep sentences short for clarity .
Long sentences can confuse the reader.
Learn to be concise and eliminate unnecessary words and cliches. Carefully and correctly use quotation marks, periods, commas, etc. Open and close your parentheses. Insure that periods follow complete thoughts. Most word processors include grammar checkers.