The drummer of the band at the party says to the lead singer: "You look like Lestat!" (because of his clothes). This is a reference to Interview with the Vampire: The Vampire Chronicles (1994).
When Amanda comes down the stairs her hair is done. In the next shot when she reaches the bottom of the stairs coming in to the yard, her hair is very flat. Then Preston says "Amanda, I love you" she turns around and her hair is done again.
At the beginning of the movie, several characters (including Preston) are introduced with yearbook entries. Toward the end of the movie, we see Preston's entry in the actual yearbook. The two almost match, but not quite; the actual yearbook includes French Club, but this is omitted from the introductory bit.