I’m not sure this is the point of the essays. It is not to demonstrate world record-breaking achievements, or some rare personality element that is extremely uncommon. Even if the essay is supposed to be about an extracurricular activity or work experience, the essay is meant to give the admissions committee a sense of who you are. In the vernacular you could say it’s supposed to be “a window into one’s soul.”
Of course, it goes without saying that essays should be flawless in terms of vocabulary, spelling, and grammar. But, depending on the topic, a looser style of language may be acceptable, even appropriate.
An essay can be effective if it shows the innate drive or passion, and how that drive or passion has shaped the applicant.
My older son’s Harvard essay was about how the study of the classics was valuable for the study of engineering (he started out with a joint concentration in both fields). The essay so successfully wove classical themes through the discussion that the Admissions Committee sent the essay to the Classics Department for their review and input.
In a short answer essay he talked about his modest abilities of juggling and unicycling.
In my younger son’s essay, he talked about his love for math. He had no great achievements with which he could demonstrate his love for math, but communicated his strong will and how it applied to studying math.
In terms of providing “a window to the soul,” one of my favorite essays was my older son’s (classics and engineering major) Notre Dame essay. The prompt was something like “Take a risk.” He wrote it in Latin. He had a lot of fun with that one.
Don’t write your essays to try to demonstrate that your the best and greatest, to get the Admissions Committee to pick you. Don’t write it with the goal of getting into Harvard, or any particular school. Write it to give them a look at who you really are.
If you do that accurately, the Admissions committee will know two things about you: the shape of your personality and character, and that you know yourself well enough to communicate it accurately and honestly. That second thing is a great prize, whether you get into Harvard or not.