It is often said that Americans are slightly ignorant when it comes to international protocol. Whether or not we travel, we should all know how to address a letter going abroad.
It is such a pleasure to receive an interesting envelope in the midst of bills and junk, and a personal note is a gesture any culture appreciates. But there are rules we must adhere to in order to get that letter there. The most basic is to write your information legibly. Never use pencil to address an envelope, or place the postage and address on opposite sides.
If the destination does not speak English, you still must write the country's name in English. The US Postal Service can then sort your letter appropriately, after which point its the receiving country's issue. If you feel comfortable writing the town and postal code in English as well, write them below the line written in the other language. This is not a huge issue because most countries (China, Russia, and Arab speaking) can process mail written in Roman letters, so do the best you can.
The address should not be more than five lines; the top line should contain the most specific information - the addressee. Your address should work itself down line by line to the most general information - the country. The destination country is written out fully on a line all by itself, preferably in capital letters. Town, Province, and postal code go together on the line above country.
Miss Phoebe Phlower
Arts and Humors
38 HaveANiceDay St.
BrokenHearted 339 A47
And just in case, always include your return address! The USPS has some more suggestions for addressing mail.