You will writer many different types of letters as you progress through your job search. The follow section describe one of them
Thank-You Letter
Expressing appreciation is very effective form of job search communication. While it may sound trite, you can say thank you at every step along the way. Everyone knows to send a thank-you note after interviews, but too few communicate their gratitude before then. A thanks for confirming receipt of your resume, including an expression of continued interest and a clearly articulated wish for a telephone or a face-to-face interview, is usually the first of these efforts.
A thanks for clarifying status, including an expression of continued interest, with a statement regarding when you might follow up again, is most likely the second. Too often ignored, a thank you for a rejection letter or email is also appropriate. Respond to a "your background does not match" letter or email with an "I remain very interested in your firm, hope at a future date my qualifications might be appropriate for other opportunities" statement. Be careful of tone, but do seek continued consideration as well as some additional focus.
Appreciation should always be expressed to network members and advocates who have referred you to postings or persons. By keeping these individuals informed of your efforts, you inspire their own follow-up efforts. Follow-up calls or emails by network members to their contact requesting special consideration often lead to interviews and speed up an otherwise slow process. In many ways, your follow-up networking letters are as important as those to organizations you wish to work for.