Even after a stellar interview, candidates will often not be called for a follow-up meeting unless they send a thank you letter. A thank you letter is a common courtesy, but your letter cannot be common or generic! It needs to be specific. This means it should be addressed directly to the people you spoke with, reiterate specific topics discussed, and touch on any relevant issues that did not come up. A great thank you letter will motivate an employer to schedule a second interview.