Possibly the best thing that one could do in the college admissions process is to start early, and start well. Too often over-achieving students procrastinate starting their application essays until a couple of weeks, days, or even hours before they are due. Don't do this! A well-written essay, of the type that will get you into really great schools, can be the tipping point in your admissions decision. Of course, there are a few exceptions, where a truly gifted writer can create a phenomenal essay in a short amount of time. But chances are, when one gives themselves time not only to write but also to think about what to write, essays tend to be better written, better informative, and better developed. Since there is a whole slew of students applying to the top colleges with nearly identical GPA, test scores, and extracurriculars it is important to add a personal element of uniqueness. With the essay, colleges are able to get an insight into who you are as a person. A bland, unexciting essay can surely hurt your chances, while a crafty and insightful essay could change that rejection into an acceptance.
Additionally, more time preparing an essay can give you new ideas about how to approach it. Often unique ideas/takes to a prompt can only be found upon delving deep into your creative side. And admissions officers love creativity. If you look at the essays that have garnered the best admissions decisions, many of them have a matchless story, a unique organization/layout, or an interesting response to the prompt. Talking about a trip to the grocery store, if spun the right way, could make for an amazing essay. The most important thing I can impart to you is this: whatever you do write about, make sure it is something that no one else will be writing about. Or if it is a popular subject, make sure your essay is bulletproof in message and in grammar.
Another reason to start early is to organize yourself. Have you collected your recommendations? Have you taken all of the tests necessary? Have you applied for a fee waiver (if needed) yet? While these may seem like simple things, you might be surprised that they have slipped your mind. Getting a jump start reviewing checklists and compiling your Common Application can lead to less stress and more time for essays later on. Get the core part of your application(s) done, and you will likely have more time to come up with stellar essays in crunch time.
Picture this: an admissions committee is reviewing two applications for admission to their top-tier college, and they are debating which person to give their last spot to in the upcoming class. One student has amazing test scores, a solid GPA, unique extracurriculars, and a pleasant essay. The other student has okay test scores, a good GPA, boring extracurriculars, but a very humorous and delightful essay. Which student will the college admit? Should they admit the kid they know can handle the workload, and excel at their school, but they don't have quite the insight into his/her personality? Or should they admit the student they know will have to work hard, but they also know the person's inner character and drive? This is a gamble that admissions officers like to make. Once students are over a certain threshold of competitiveness with the objective statistics (SAT, GPA, AP's, SAT II's) they look more for who you are as a person rather than as a student. Remember this, and you might just be able to get into your dream college.