If you are applying to more than one program, you may find that each application asks a different question or set of questions, and that you don't really feel like writing a bunch of different responses. However, you should avoid the temptation to submit the same essay for different questions—it's far better to tailor your response to each question and each school.
If you do find yourself short on time and must tailor one basic essay to fit a number of different questions from a number of different schools, target your essay to your first-choice school, and keep in mind that the less your essay is suited to an application's particular questions, the more you may be jeopardizing your chances of being admitted to that school.
Be honest and confident in your statements.
Use positive emphasis. Do not try to hide, make excuses for, or lie about your weaknesses. In some cases, a student needs to explain a weak component of his or her application, but in other cases it may be best not to mention those weaknesses at all. Rather, write an essay that focuses on your strengths.
Write a coherent and interesting essay.
Make your first paragraph the best paragraph in your essay.
Develop a thesis about yourself early in the essay and argue it throughout.
Each piece of information you give about yourself in the essay should somehow support your thesis.
Pick two to four main topics for a one-page essay.
Don't summarize your entire life. Don't include needless details that take space away from a discussion of your professionalism, maturity, and ability to do intellectual work in your chosen field.
Use the personal statement as a form of introduction.
Think of the essay as not only an answer to a specific question but as an opportunity to introduce yourself, especially if your program doesn't interview applicants.
Ask yourself the following questions as you edit for content:
Are my goals well articulated?
Do I explain why I have selected this school and/or program in particular?
Do I demonstrate knowledge of this school or program?
Do I include interesting details that prove my claims about myself?
Is my tone confident?
Make sure your essay has absolutely perfect spelling and mechanics.
Use technical terminology and such techniques as passive voice where appropriate.
You should write clearly and interestingly, yet also speak in a voice appropriate to your field.
Write what you think the admissions committee wants to hear. You are probably wrong, and such a response is likely to make you blend into the crowd rather than stand out from it.
Use empty, vague, over-used words like "meaningful," "beautiful," "challenging," "invaluable," or "rewarding."
Overwrite or belabor a minor point about yourself.
Repeat information directly from the application form itself unless you use it to illustrate a point or want to develop it further.
Emphasize the negative. Again, the admissions committee already knows your GPA and test scores, and they probably are not interested in reading about how a list of events in your personal life caused you to perform poorly. Explain what you feel you need to, but emphasize the positive.
Try to be funny. You don't want to take the risk they won't get the joke.
Get too personal about religion, politics, or your lack of education (avoid emotional catharsis).
Include footnotes, cliches, or long-winded and slow introductions.
Use statements like "I've always wanted to be a…" or any other hackneyed phrases.
Use gimmicks—too big of a risk on an application to a graduate or professional program.
Allow any superficial errors in spelling, mechanics, grammar, punctuation, format, or printing to creep under your vigilant guard.