HU, more than any other situation, you play your opponent and mix up your game. Raise some good hands, raise some bad hands, bet some hit flops, slow play some hit flops. Harrington says it's a mistake to fold anything from the small blind, but I still do it, partly 'cause I'm not Action Dan, partly to keep mixing up my play at the cheap SnGs I play.
There is no one way to play HU, other than reading your oppenent, being flexible, and mixing it up. Use whatever plays you have in your arsenal that you think might work against the particular opponent you have that particular day.