Brush up on your cursive writing. Believe it or not, there have been numerous studies on written exams. Those students who use cursive writing tend to do better by many points, depending on the test and scale used to grade it. Some educators believe you are able to keep up with your thoughts more precisely using the connected cursive words. This helps eliminate incomplete thoughts and sentences.
Have a good grasp on what you are supposed to be writing about. Read the prompt very carefully and be relevant with your answer. Double check that all parts of the prompt are answered thoroughly in your response.
Understand the audience to whom you are writing. This is a test for college or university admittance. This is the time to be as professional and articulate as possible. Avoid using slang and all abbreviations. You do not need to try to sound smarter than you are, but write to impress your audience and accentuate your strengths.
Edit with extreme caution. Allow yourself plenty of time to make sure that all of your words are legible, the spelling and punctuation is as correct as you can make it and that incomplete thoughts or sentences are corrected. Fragments and run-on sentences can lower your score and make you sound less credible and intelligent.
Be bold. Stretch the truth if you need to make a point. If the prompt does not directly pertain to you, do not be afraid to stretch the truth a bit to answer the question or directions completely. Do not make up outrageous tales that are unbelievable, but if you have to, use another's experience or imagined experience to highlight your best reasonable answer.