You may also view your thank-you letter as a follow-up "sales" letter. In other words, restate why you want the job, what your qualifications are, how you might make significant contributions, and so on.
While you can include both a thank you and a sales pitch in your letter, keep it short. This is not another cover letter, but instead a concise way to remind the employer why you’re the right choice for the job.
In certain circumstances, you may want to send a more detailed influence letter, which includes additional information on your skills and qualifications for the job.
Check your spelling and grammar before sending your letter. If in doubt about the correct names, spellings, or titles of your interviewers, call the office to double-check.