The post-interview thank you note is one of the most important steps towards landing your dream job, but it's a "surprisingly often overlooked step for candidates in the application process," according to Brent Kleiman, CEO of Argosight, a company that provides talent acquisition services.\nKleiman isn't the only one who finds a lack of post-interview thank you notes confusing. A number of career experts mention the thank you note when asked what you must do after an interview.\nIt can make or break your interview, says Bonnie Treece, owner of The Brain Domain LLC, a company that provides tutoring services. "If two similar applicants apply and one takes the time to send a thought-out thank you note, nine times out of 10, I will hire the person who took that time."\nIt's an important step in the interview process, and one you can't ignore. But what are the rules of the post-interview thank you note, and what should you include when following up with a hiring manager or recruiter?\nWait until after the interview\nThis might seem obvious, but don't try to save yourself some time by pre-writing a thank you note before the interview. It will probably wind up sounding impersonal. "I've seen candidates interview and at the end of the interview hand the manager a thank you note. Make sure the thank you note is genuine and personalized," says Noelle Cipollini, Director of Recruiting at Kavaliro, a firm that provides staffing services.\nHow soon do you send the note?\nMost experts agree that you should send the note within a 24-hour window. Don't type it up in the car on your phone in the company's parking lot, but do try to send it within a one-day window. You want to make sure you are still fresh in the interviewer's mind, so your follow-up should be timely.\nA thank you note for everyone\nChances are that you worked with a number of different people through the interview process, so you will need to send more than one note. If you worked with a recruiter or someone who facilitated the interview, be sure to send them a thank you note as well as the hiring manager.\n"Send thank you [notes] to each person you were interviewed by -- not a group thank you. Contact the receptionist or administrative assistant to get names if you don't already have them," says Cachet B. Prescott, r\u00e9sum\u00e9 writer, career strategist and workplace trainer.\nProofread the note\nMake sure you proofread your note, especially if the job calls for an attention to detail. Someone might ignore a typo in an email once you're on the job, but any communication between you, a recruiter or hiring manager during the interview process will be closely scrutinized.\nHighlight parts of the interview\nMention part of the interview in your thank you note. Whether you reference a topic of conversation or a particular skill, make sure they know you were engaged during the interview. It also shows that you put thought into your note, and aren't just sending it as a formality.\n"Restate your interest in the position and why; you shouldn't assume that they think you're still interested," Prescott says. "Try to tie in something that was discussed or that you learned throughout the course of the interview -- but don't force it. The inclusion should come organically."\nThank them for their time\nJust as you had to take time out of your schedule to go in to interview, your interviewer had to take time out of his or her schedule to meet with you. Make sure you acknowledge this and show you appreciate the fact that they made time for you in their busy day.\nEmail or Snail Mail?\nA handwritten note might traditionally seem more personal, with today's electronic communication, a handwritten note could take too long to land on the right desk. And most career experts reference timeliness when it comes to sending your thank you note.\n"Some may believe a written thank you sent via snail mail is more impactful. This may be true, but the purpose is not impact; it is to communicate your interest and to provide a timely response," says Lora Kratchounova, principal at Scratch Marketing + Media, a marketing consulting company.\nYour post-interview thank you note doesn't need to be complicated, but it does need to be sent. Ignoring this step might cost you the job, so make sure to send out a thank you after your next interview.