Med-school admissions counselors read a lot of essays. It doesn't help that many applicants *do* have a lot in common with one another. Due to the intensity of medical school, for example, odds are that you've wanted to be a doctor for a long time--it's not the sort of commitment anyone makes lightly.
There's nothing wrong with expressing that, says Geoffrey Cook, founder of EssayEdge.com, but "don't offer your point in such a cliched, prepackaged way as to make your reader cringe. For example, you shouldn't start your essay, 'I have always wanted to be a doctor' or 'I've always known that medicine was my calling.' Better to describe early experiences and then let your interest unfold naturally."
An essay isn't a list. Don't just reel off the attributes that you think would make you a good doctor; instead, discuss "concrete experiences that show your abilities and qualities. As always," says Cook, "details are paramount."
Focus on what you did, rather than a project as a whole--your specific contributions are what the admission officers are looking for.
You're writing to communicate, not to impress the admissions counselors with all the ten-dollar words you know. Focus on getting the idea across; don't use two words where one will do, and don't use a long word when a short one would work.
"Many candidates try to dodge tough questions," IvyLeagueAdmission.com says, describing a summary of a survey they did of medical admission officers, "particularly those about ethical issues, personal weakness and failure. Yet the committee asks those questions for a *reason*. We want to understand how you respond to adversity and the specific insights you developed from those experiences. Answer the tough questions honestly and directly."
Medicine is a field where small errors can have major consequences; a careless doctor isn't a good one. You're writing your application essay on a computer with time to revise and check, not in an exam room; there's no excuse for typos or grammatical mistakes, and they send a bad sign to admissions officers about your level of attention to detail.
Don't just rely on spell check; run your essay past some friends to make sure that it's as clear and effective--and error-free--as you hope.