(AP) — The SAT scores are in, the GPA is established, teachers' impressions are formed, and there's only limited time to beef up the resume of extracurricular activities and community services.

By the time high school seniors start filling out their college applications, much of what admissions officers will use to give a thumbs up or down is set. No wonder there's such angst over the college admissions essay.

So much so that assisting students with their essays has become a big business, the subject of books and counseling and editing services.

How much does the essay really matter?

“Applicants and their families have somewhat of a belief in the redemptive value of the essay,” said Barmak Nassirian, associate executive director of the American
Association of Collegiate Registrars and Admissions Officers. “It's an urban myth that a student who has goofed off his whole academic career can get in with a come-from-behind epic struggle in which the essay serves as the primary tool.”

“It's not a substitute for a rigorous curriculum, good grades and evidence that you're going to do well,” he said.

Still, the essay can make a difference.

At the University of Virginia, Parke Muth, the associate dean of admissions, talks about the “10 percent rule.”

“If you have 18 – or 20,000 applicants, for some of those students, the essay makes a huge difference, both positively and negatively,” he said.

Admissions counselors at the University of Virginia read every essay looking for the student's voice.

The first challenge for the writer: picking a topic.

Any topic can work — or fail, Muth said.

“It shouldn't be an essay about community service. It should be about a moment of time,” he said. “Start writing an essay about John who you met at a homeless shelter who talked to you about his life. Like any piece of good writing, then you're going to make that come alive.”

The biggest problem for students, he said, is starting with too wide a focus. “By the time they get to the details, they run out of space,” he said. “I'm all for cutting to the chase.”

Many schools ask open-ended questions.

Last year's common application, used by scores of colleges and universities around the country, asked students to discuss an issue of personal concern, a person, fictional character or historic figure who influenced them, a life experience or a topic of their choice.

Hilary Brandenburg, who will attend New York University in the fall, wrote about her summer internship at fashion house Liz Claiborne in New York. “I used my experience as a way to frame myself and what I was interested in studying at the schools that I applied to,” said Brandenburg, 18, of Washington, D.C.

“I had a lot of different topics I started,” she said. “At school we were told to come up with a list of anything we thought would be interesting about ourselves. We went through a lot of workshops and they gave us prompts and then we had to think about ourselves”

She said her internship “was the easiest thing for me to write.”

Brandenburg said her biggest frustration was keeping within the word limit. “In the end, it helped me refine what I wanted to say and it became more to the point,” she said.

Muth advises students to read their completed essays to their best friend. If it sounds like them, they've probably done a good job, he said. “If it sounds like a Ph.D. thesis, it's probably not their voice, the voice we're looking for.”

It's OK to seek feedback from a couple of people, he said, but don't overdo it.

“I think increasingly we're seeing essays by committee,” he said. “They've written a draft for their high school English class. Then their high school counselor looks it over, Mom looks it over and Dad looks it over and a friend. By the time it goes through that many people, the life is out of it.”

Then there are those who seek assistance from professional counselors or the essay companies that have cropped up.

Nassirian said college admissions officers have become good at “detecting paid embellishments” to essays.

College-Admission-Essay.com is one Internet site that offers students help with their essays.

“Imagine standing out amongst a pool of thousands of essays and applications –  the odds of beating mediocrity to become a sure pick for the colleges thus becomes a high-pressure challenge,” customer representative Kathy Joon said in a written response to a question about why services such as her company's are needed.

She said company counselors know what admissions officers are seeking and how to “elaborate the achievements and strengthen the grammar, context and content of the essays, so that they stand out apart from the numbers and details of their application.''

College-Admission-Essay.com charges students $199 to have a professional writer edit a 500-word essay. For services from a counselor, the company charges $150 per hour, with discounts for multiple hours. The counselors also provide general college counseling.