Sarah Stamboulie. a New York career consultant, had a young Japanese client whose work visa was due to expire in just six weeks. The man was determined to find work at a hedge fund that would allow him to stay in the U.S. but he spoke with a strong accent, his written English was poor, and he had made a weak impression at job interviews. Stamboulie, who has worked in human resources departments for both corporations and nonprofits, encouraged him to follow up with an interviewer at a Japan-based fund who had already turned him down. Impressed by the young man’s persistence, the hiring manager recommended him to another Japanese fund that had an opening. Stamboulie’s client got the job. “It was like a semi-hostile referral, but it worked,” she recalls.

Lesson learned: Following up on a job interview is crucial. Even if you blow the interview, it pays to get in touch after the fact.

Ideally your interviews always go smoothly, and after each one you craft an effective note thanking the interviewer for the time, expressing enthusiasm and making it clear you listened closely to the hirer’s requirements. “The follow-up letter is almost like a proposal letter,” Stamboulie says. You should tailor it to the company and suggest specific ways you can address the needs you discussed when you met.

Roy Cohen. author of The Wall Street Professional’s Survival Guide: Success Secrets of a Career Coach. agrees that a follow-up note should always focus on what the hiring manager’s looking for. “You should say, ‘I listened, I understand your needs and your challenges, and here’s how I can help you address those,’” he says. Concisely remind the interviewer of what you’ve accomplished in the past, and make a couple of concrete suggestions for how you can help the company.

Do send the follow-up note as soon as possible. “If you don’t, someone else may send a message more quickly,” Cohen advises. If you don’t have time to craft a longer note, consider sending a short thank-you immediately, mentioning that you want to give further thought to the challenges you discussed and promising to send a more in-depth message soon.

Do send e-mails rather than handwritten notes, Stamboulie and Cohen agree. “People say that snail mail stands out, but it stands out for the wrong reason,” Cohen says. “It will make you look like a dinosaur.”

If you’ve met with more than one person in the interview process, think about what will make for an appropriate note to each, Cohen advises. For instance, if you interviewed with someone who would be reporting to you if you get the job, you can say something like, “It sounds like you’re working on some interesting projects. It would be great to have you as a colleague.”

David Couper. a career coach in Los Angeles and author of Outsiders on the Inside: How to Create a Winning Career Even When You Don’t Fit In. recommends a different tack if you’re following up on a meeting with human resources staff, as opposed to a hiring manager. HR professionals tend to struggle with overloaded calendars. He says it’s always a good idea to send a follow-up e-mail, but if the interview was at a large company, “don’t be surprised if you don’t hear back.” He recommends asking the HR person during the interview how he or she would like you to stay in touch.

Couper also suggests leapfrogging over HR if you get no response to your follow-up note. A client of Couper’s who was interviewing for a vice president-level job at an entertainment company did just that recently. It took several phone calls, but he eventually got the hiring manager to put pressure on the overworked HR team to hire him. He got the job.