I am not old for this yet but on Tumblr I have seen that this has worked for many people, and they say it is very important.
They say that after an interview it is good to send an e-mail or letter to thank the company or person who interviewed you.
So here I leave you a "base" as it should be, this I took from Tumblr;)

Dear ______: Thank you so much for the opportunity to sit down with you (& ________) to discuss the [insert job position]. I am grateful to be considered for the position. I think I will be a good fit at [company name], especially given my experience in __________. [insert possible reference to something you talked about, something that excited you.] I look forward to hearing from you [and if you are feeling super confident: and working together in the future]. Sincerely,
(put your name here)

I hope this help!