An obvious essay question on your law school application may be entitled "Why I Want to Be a Lawyer." You cannot just state why and expect it to be enough; you will want to provide the admissions officers with a thorough explanation. They want believable life details, and even if your reasons for becoming a lawyer aren't unique (such as your dad was one), admissions officers want your take on it to be interesting.
"Why I Am Qualified" is another essay topic, similar to "Why I Want to be a Lawyer." Getting some experience in the law field is recommended before applying to law school, and essays about direct experience--such as an internship at a law firm--show the most commitment to the field. However, political volunteer activities or helping on a campaign can provide material for good essays. Also, if you have lots of experience, don't try to list it all in your essay. It is better to focus on the experience that meant the most to you,
Another potential essay topic is "Why I am an Exceptional Person." This is the time to say whether there is anything unusual about you or your circumstances. People of foreign backgrounds or older or disabled applicants can use this topic to their advantage. You can always write about an exceptional trait or skill, too.
Another type of essay is issue-based. Law school admissions officers like to see passion and knowledge in subject areas. Not only does an issue-based essay give an admissions officer a glimpse into your personality, it shows your potential for succeeding in law school by arguing a case.