Scholarship donors and admission officers want to know more about their students than statistics and dry facts. Essays are an extremely important part of the admission and scholarship selection process, simply because they are the most immediate indication of who and what you are.
To begin, you are writing for a purpose; you are trying to convince either an admission officer, or a committee, that by virtue of your merit (academic achievement, athletic prowess, leadership interests, etc.) they should either admit you into their school, and/or award you money. In order to accomplish this, present yourself as clearly and fully as possible. Your personal essay should be dedicated to expounding your good qualities and achievements.
Committees and admission officers are impressed with personal growth and individuality. If you think that cannot possibly mean you, think again - it does. You are not the same person you were one, two or three years ago. You have matured, you probably have more family and/or work responsibilities, and you probably have become more involved in your academics and outside interests. If this weren’t true, you wouldn't be thinking about attending college, and you wouldn’t be reading this now. So think positively, and brainstorm! Don’t worry whether or not what you have to say is important enough or particular enough to catch someone’s attention. If you are writing about something that you truly care about, it will be interesting and worthwhile.
If you are applying for admission to college, you may be asked to write about these topics:
If you were writing on the last topic, you would want to tie together your desire to further your education and why that school is the best place for you. For example, you may want to write on the recent changes in the Soviet Union. You would first briefly discuss the importance of those changes in world politics. Then secondly, you would state how they relate to your interest in diplomacy (if that is true), and how, since their school has a particularly strong international relations program (if that is true), their school is particularly suited to filling your interests and career goals.
If you are applying for a scholarship offered by a private foundation (or by a school or university), consider the source. For example, if the Daughters of the American Revolution offers scholarships, what do you think they might ask you to write on? They are undoubtedly a patriotic organization; perhaps you should brush up on your U.S. history and government. If you are writing on a specified topic (e.g., “The Importance of Education to Minorities in the 21st Century”), you may need to do some research and reading. Whether or not you are answering a specific question, being aware of and tying pertinent news and events into your essay helps.