Purdue University has an excellent Online Writing Lab.
Look it up!
Here is some good advice from there:
Answer the questions that are asked
- If you are applying to several schools, you may find questions in each application that are somewhat similar.
- Don’t be tempted to use the same statement for all applications. It is important to answer each question being asked, and if slightly different answers are needed, you should write separate statements. In every case, be sure your answer fits the question being asked.
Tell a story
- Think in terms of showing or demonstrating through concrete experience. One of the worst things you can do is to bore the admissions committee. If your statement is fresh, lively, and different, you’ll be putting yourself ahead of the pack. If you distinguish yourself through your story, you will make yourself memorable.
- Don’t, for example, state that you would make an excellent doctor unless you can back it up with specific reasons. Your desire to become a lawyer, engineer, or whatever should be logical, the result of specific experience that is described in your statement. Your application should emerge as the logical conclusion to your story.
Find an angle
- If you’re like most people, your life story lacks drama, so figuring out a way to make it interesting becomes the big challenge. Finding an angle or a “hook” is vital.
Concentrate on your opening paragraph
- The lead or opening paragraph is generally the most important. It is here that you grab the reader’s attention or lose it. This paragraph becomes the framework for the rest of the statement.
Tell what you know
- The middle section of your essay might detail your interest and experience in your particular field, as well as some of your knowledge of the field. Too many people graduate with little or no knowledge of the nuts and bolts of the profession or field they hope to enter. Be as specific as you can in relating what you know about the field and use the language professionals use in conveying this information. Refer to experiences (work, research, etc.), classes, conversations with people in the field, books you’ve read, seminars you’ve attended, or any other source of specific information about the career you want and why you’re suited to it. Since you will have to select what you include in your statement, the choices you make are often an indication of your judgment.
Don’t include some subjects
- There are certain things best left out of personal statements. For example, references to experiences or accomplishments in high school or earlier are generally not a good idea. Don’t mention potentially controversial subjects (for example, controversial religious or political issues).
Do some research, if needed
- If a school wants to know why you’re applying to it rather than another school, do some research to find out what sets your choice apart from other universities or programs. If the school setting would provide an important geographical or cultural change for you, this might be a factor to mention.
Write well and correctly
- Be meticulous. Type and proofread your essay very carefully. Many admissions officers say that good written skills and command of correct use of language are important to them as they read these statements. Express yourself clearly and concisely. Adhere to stated word limits.
- A medical school applicant who writes that he is good at science and wants to help other people is not exactly expressing an original thought. Stay away from often-repeated or tired statements.