Merito Group is a boutique talent acquisition firm based in the Washington D.C. area. We understand that candidates face a lot of pressure when applying for a new position and that is why we offer individualized coaching to help candidates gain the confidence to crush their interview. But when it comes to impressing a potential employer, performing well during the interview is only half the battle.

In fact, bestselling management author and CNBC contributor Suzy Welch believes that it’s actually what you do after an interview that can “make or break your chances of getting an offer.”

Below, she shares the steps that every candidate should take within 12 hours of their interview — plus one blunder she says you’ll want to avoid at all costs.

1. Write a thank you note

Thank you notes are critical to showing an employer you appreciate their time. That’s why Welch says you should send a personalized thank you note to every person you interviewed with immediately after your meeting.

“Guess what? Hiring managers often compare thank you notes,” she says. “So no cutting or pasting.”

2. Edit your social media accounts

The way you present yourself on social media can have a huge impact on whether you get hired. To ensure that your online presence is in tip-top shape, Welch says that you should review your accounts “as if your interviewer is combing through them,” because, she says, “they most likely are.”

“After your interview, post intelligent tweets about your industry or the economy,” she advises, “and please, avoid stupid Instagram pics.”

3. Connect on LinkedIn

Welch recommends sending your interviewers an invitation to connect on LinkedIn, along with a message that refers back to your meeting.

“Don’t just click a button,” she warns. “Say something about how much you enjoyed meeting and discussing x, y or z.”

To read more of Suzy Welch’s valuable advice on CNBC, click here.