What is the proper way to address an envelope to a 12 year old boy?

In the center of the envelope, on the side without the flap, write a line containing his name, and then on a line below that, write his street address. On a line below that, write the city, state/province/, and country in which he lives. On the same line OR on a line below that, write his zip code. In the upper left hand corner, write the same information about yourself. This is called a 'return address', and will only be used if the letter for some reason needs to be returned to the sender (you). By the way, these instructions apply to virtually EVERY letter you will ever need to send, unless it's to a business or something.