About Julia...
I am a landscape architecture student at a University in the state of Florida! I really enjoy architectural postcards and postcards of parks. I am also very interested in world culture, so traditional folk art would be a good choice. Mythology as well.
But I will be very happy with anything! I love receiving postcards of any interest! I also do not particularly care about stamps, but I appreciate any effort put into the selection of stamps.
As for what to write, that is up to you. If you need ideas, you could recommend a book. I enjoy almost all books, even reference and non-fiction. I would also enjoy reading about some of the history of where you live, or a local superstition or custom.
Additionally, if it is not too difficult, I would appreciate a coin or something small from your country! An envelope is fine to use, in fact it is preferred.