I have close friends in USA and New Zealand, I always make sure that I send special parcels every christmas. My friend in NZ used to live in England which is how I know her, so I make sure I send her British food treats that she can't buy over there.
I also make sure I send a text message to them at christmas, new years, on their birthdays (and a card on their birthdays too.) I will also post messages on facebook for all my friends, and wish all my American friends on facebook a happy thanksgiving.
I try to do web chats but I live in a flight path and it's so hard to keep the video link working. Such a shame.