Always, always, always send a thank-you letter immediately after a job interview. The reason for sending a thank-you letter following a job interview is threefold. First of all, it's the polite thing to do. The interviewer has taken time out of his busy day to meet with you. Secondly (and most important) is that a thank-you letter gives you the chance to reiterate why they should hire you. You can also use the opportunity to call something to the interviewer's attention that you didn't discuss on the interview. Finally, sending a thank-you letter will make you stand out in the employer's mind. When he is deciding between hiring you and hiring another candidate with similar qualifications, your thank-you letter will give you the edge.
You should send your thank-you letter by e-mail, but if you can't, send a typed letter using the format described in Chapter 7. Remain formal — don't address the interviewer by his first name. Even though you have already met him, you shouldn't be on a first-name basis at this point.
If more than one person interviewed you, you should send a thank-you letter to each one. Jot down their names before you leave the office if possible. Check with the receptionist to get the proper spelling. Each letter should be personalized. That means, don't say exactly the same thing in each one. Talk about something that is relevant to a question the recipient asked, or something that would be important to her.
When someone helps you in your quest for a new job, you should also send a thank-you letter, whether or not that person's help leads to your getting hired. Send a thank-you note to a network contact who helps you get a job interview immediately after the interview. That will give you the opportunity to let her know how the interview went. It may also spur her to contact the employer to put in a good word for you. Send thank-you notes to anyone who provides a reference to a potential employer on your behalf.