I help high-school seniors write their college-admission essays. Here are the 4 most common mistakes to avoid.

• For eight years, I've worked with high-school students to perfect their college-admission essays.
• I often see students think their ideas are completely original; the ideas have been done before.

For high-school seniors, one of the toughest parts of the college-application process is writing the dreaded personal essay.

For eight years, I've been helping students shape their college-entrance essays. I help them home in on ideas that work, and I edit the essays to make sure their stories make sense. Lastly, I work with students themselves to buff and polish the essays until they shine.

Through my years working with students, I've noticed several common mistakes. Here are the four pitfalls any prospective college student should avoid when writing a personal essay.

Think your idea or topic is original, but everyone is actually writing the same thing

Your personal experience may be unique to you, but it may not make a unique college essay.

For example, in my area, there is a huge South Asian immigrant population. These kids are first-generation Americans and were brought here as small children or were born right after their parents arrived. These first-generation Americans want to share their stories because these are important, meaningful stories. Unfortunately, though, the idea isn't original. On average, approximately 70% of my students are trying to write on the same topic.

Similarly, students often think writing about someone else — a role model, for example — will be original. I assure you, it will not. Yes, you have deep respect for your grandmother who raised five children as a single mom, but that's her story, not yours.

You're writing about an experience that happened when you were in elementary school

I've seen high-school students write about how they learned to be part of a group when they joined a robotics club in third grade. Unfortunately, the admissions counselors don't really care about third grade. They're interested in your current life — as a high schooler.

You want to write about things that have happened to you recently. Did you just have a big blowout with your friend group that redefined your meaning of friendship? Did you find out that your best friend cheated on a recent chemistry exam? What did you do about it?

Tell us who you are today — not who you were in elementary or middle school.

You want to focus on your achievements, your SAT scores, or your grades

Showcasing your academic triumphs is what the rest of the application is for. From transcripts to letters of recommendation to a list of your activities, admissions officers will see your accomplishments throughout your application.

But if you rewrite them in your personal essay, you'll just be repeating yourself, which colleges don't like. Plus, you won't be showing who you really are.

You're not thoroughly proofreading your essay

Reading the essay back to yourself under your breath isn't enough. I want you to first read the essay out loud — one word at a time and slowly. I want you to then read it out loud to yourself again, but this time, read it backward so that you see each word as a separate entity. Finally, I want you to use free spell-check programs, like Grammarly. And then reread it again before hitting the upload button.

With all that said, make sure you're showing who you are in your college essay. Bring yourself to life. Use the power of storytelling; it will get you everywhere.

Do you have a powerful or unique college life story to share with Insider? Please send details to folito@insider.com.