Timing is important
You have a couple of days to write a Thank You note. After just a few days have passed, the recipient is more likely to remember you and your conversation. As time passes, memories fail and your Thank You note could look more like a sales mechanism than a sincere gesture of gratitude. Try to get your note out as soon as possible.
If you waited too long
If you waited too long, don’t despair. Send a Thank You note anyway and add a bit of humor:
You get the picture. If you’ve waited too long, be self-effacing, apologize, and–as always–show your sincerity.