Psychochild just tackled this very topic over on his blog as he watched his better half get addicted to playing Lord of the Rings Online. While she avoided the temptations of Meridian 59 and World of Warcraft, Psychochild notes that it was a familiar setting that got her into the game.
From there she did the standard things, such as close tutorial boxes and try to familiarize herself with the in-game vocabulary, but she also noted some very interesting things about the design itself. Things like the inconsistency in group quests, where sometimes the whole group can loot an item but other times the item is dropped for one person and one person only. Or how the game doesn't always embrace the entire group in a quest, such as the infamous Hobbit pie quest.
For Psychochild's full account of her gameplay, check out the full story over on his blog.