How many times have you heard, “Don’t forget to say thank you?” When we were children, adults reiterated it over and over again. Yet, somehow, as adults, we are forgetting this simple lesson.

The Wall Street Journal recently cited a poll that found 75 percent of employers that were surveyed complained that job applicants didn’t send thank-you notes after an interview. In addition to the after-interview thank-you notes, I have seen this trend inside cover letters. We are increasingly leaving out the thank you at the bottom of our cover letters.

The crazy thing is, a thank you is essentially free to give. It doesn’t require going back to school or paying for some expensive certification. It’s a simple acknowledgement of someone’s time and consideration.

But, given that we all mean well, I have to think that this trend is not intentional. It has to be connected back to how busy we all are and how blurry the lines have become about social rules. We focus on being the most qualified candidate rather than the easiest to get along with. Yet, we know that hiring managers are people too. And their decisions are often based on little things, like first impressions.

Given the importance and the simplicity of the thank-you, here are a few guidelines.

First, include a thank you in your cover letter. For example, near the end, you could say, “Thank you for taking the time to review my request.”

This thank you is important because the hiring manager is very possibly reviewing hundreds of applications.

Then, as you correspond with the hiring manager, the human resources representative, or anyone else from the company, be sure to close all communications with a thank you. “Thank you for your help,” or a simple, “Thank you,” at the end of emails works great.

In person, thank the hiring manager for inviting you to interview. Thank them for their time.

After the interview, do two things. First, send electronic thank-you notes by email. These are short emails sent to each person you interviewed with, thanking them for meeting with you. This can be a great place to mention something specific that you discussed with the interviewer.

Then, follow up with a handwritten thank-you note to each person. I know it sounds old-fashioned, but it works. And it’s cheap. Include a personal message for each person, and drop in your business card. It helps to remind them about who you are.

Sending a thank-you note and a thank-you email after an interview may sound redundant. But, think of it this way: The handwritten note is the most powerful one, but it may get lost or take a while. The e-mail is the surefire way to ensure the hiring manager hears from you before they make a decision.

The best news is, with so few people sending thank-you notes, this simple gesture will make you stand ahead of the pack.

Angela Copeland is CEO and founder of Copeland Coaching and can be reached at CopelandCoaching.com.