After the interview, it’s always a good idea to send a Thank you letter. Moreover, since less than 10% of candidates usually send it, it can help you stand out from the crowd. Here are some guidelines and tips for writing your Thank you note.
You should always try to send the Thank you letter within 24 hours after the interview. While in some professional areas a physical (paper) letter is expected, in areas related to new technologies it’s common to send it through the e-mail.

Here are some tips you should follow

* Express your enthusiasm: Show your interest and enthusiasm towards the company and the position for which you were interviewed. Try to be specific about why you are interested and why you think you would be a good addition to the team.

* Mention any unresolved issue: talk about any problem or issue that could have come up during the interview and that you feel was not answered completely. This letter is your last chance to make a positive impression to the interviewer.
* Personalize the letter: you will probably be one of many interviewees, so you need to stand out and make them remember you after you leave the meeting. In your letter, highlight the key points of the interview you think the interviewer will remember and therefore, will help him remember you.
* If it was more than one recruiter, consider sending them all a different Thank you letter, with some variations, since you may not know exactly who makes the final decisions. Asking each interviewer for a business card will help you remember their names.

* Repeat information about your experience: If they mentioned their specific needs, issues or problems, use the Thank you letter to suggest ideas to solve them.

* Highlight your achievements: Similarly, if they mentioned the ideal qualities a candidate should have, use your Thank you note to remind them you possess these qualities.
* Remember to check for mistakes and make corrections before sending the letter. Make sure it shows a professional image and has no spelling or grammatical errors.