It turns out students can doom themselves by failing to answer the question an essay is asking and by telling colleges what they think they want to hear.
On the Common Application, applicants choose from among five prompts for the main essay, Abby Siegel, a college entrance consultant with 19 years of experience, told Business Insider. It reflects poorly on applicants when it's not clear what prompt they've chosen, she said.
"A lot of times I'll read essays where [I think] what question are you actually answering?" she said. "Pick a prompt and stick with the prompt."
She said the second most common trap that applicants fall into is writing what they think colleges want to hear about them, rather than writing what they want the college to know. That may sounds obvious, but she stressed how commonly she reads essays that list accomplishments rather than tell a personal story.
"This is the opportunity for students to showcase something about themselves that otherwise the admissions officers are not going to know," Siegel said.
"It can be something that's totally unrelated to everything else in the application but it should highlight part of their personality or highlight something important to them."