Be persistent in applying for a job?

There is nothing wrong with writing a thank you letter to the DON. That is perfectly acceptable.

Just handwriting a thank you note in a nice card sounds good to me. I did that after I interviewed for my current job.

Good advice from the above poster. It was nice to recieve a small thank you card from those I spoke to about positions or after interviews as those persons tended to stick in my mind if they called again for a follow-up or when I needed to pull applications for an opening. Just a small thank you card in your handwriting. Thank her for taking the time for you conversation and to hear from her in the event of a potential opening. Mail it dont email it lol. I didnt usually open most emails but I always paid attention my regular mail.