There are three schools on Haruhi viewing.
First there's "chronological" where you watch each episode in their order, regardless of when they were first shown, or which season. This is a complicated way to watch it. You should go episode Season one 0-7, season two episode 1, season one 8-10, season two 2-14, season one 11-14.
Second there's "by season" in which you watch the episodes in season one chronologically, and then watch season two, which happens inbetween episodes of season one.
Then there's "original broadcast order," in which you watch episodes 0, 1, 2, 7, 3, 9, 8, 10, 13, 4, 12, 11, 5, and 6. In that order. Then you watch season two as presented. This is more complicated than watching chronologically. It also isn't technically original broadcast order for season two, as season two was first shown during a chronological reshowing of season one. Yeah, it's that kind of show.
Oh, in any case, watch the movie, The Disappearance of Haruhi Suzumiya, after your preferred method of viewing the series.