When I taught people, I've found that going over the very basic structure of the game (objective of the game and the different phases) as fast as possible and getting into a very basic demo game as quick as possible is probably the easiest way to learn it. I think this is because all of the individual game elements are very basic but there are a lot of game elements, so its pretty easy to learn by doing and its pretty daunting just to ramble off rules.
Also, I agree with Tekwych. The starter decks are pretty good but I would probably not use the Lannister/Stark demo game. I would use the dual-house decks in the deckbuilding section. At least when I played, I felt the demo game was fairly imbalanced towards the Starks. However, the dual-house decks felt fairly balanced (except the Greyjoy/Stark deck in melee games, too much board control).