Want to leave an excellent final impression? Write out your "thank you" note immediately after the interview and hand-deliver it before the interviewer leaves at the end of the day. Final decisions for company-site callbacks are usually made the same day, so make your best case while you can still have an impact on the outcome. If you were not the last interview on the schedule, sit down in the waiting room and scribe your response on the "thank you" stationery you brought with you. Then give the card to the receptionist and ask that the card be passed on to the interviewer. If you are the last interview of the day, write a quick note and get it to your interviewer before he or she leaves (most recruiters spend a few minutes organizing the accumulated information before departing). You can even have part of the note (the "thanks for your time" opening) written ahead of time. Then track the person down before he or she leaves the building (beware of alternate escape routes!).
If you are unable to get your "thank you" card to the interviewer, call the office and ask for the interviewer's voicemail. When messages are checked that evening, your personal "thank you" will make a lasting impression. If you are unable to get through with any of the above, send an e-mail thank you to the e-mail address on the business card.
By taking these simple steps, you will definitely stand out from the crowd.