All this reminds me of what I didn't do to prepare. Take it from a return missionary that wished he did the right things, it would have helped me make my first year on my mission easier.
Getting Called To The Same Country As Your Friend
After introducing her friend to The Church of Jesus Christ of Latter-day Saints, a young woman now serving a mission in Japan was surprised to learn her friend would be serving a mission in the same country. Ref. Source 9u