For the most part, the students are played by genuinely youthful actors, almost all of them still teenagers when the film went into production, though the main exception, David Krumholtz, is the most baby-faced of the lot. Krumholtz steals every one of his scenes, and it's a pity that the the film doesn't choose to wrap up his plotline in more satisfying fashion; he disappears rather abruptly from the action. Still, seeing the emergence of actors like Julia Stiles and Heath Ledger has its compensations, and their chemistry together feels genuine.
Director Gil Junger slips into musical montage mode a little too often, selling the soundtrack rather than advancing the plot, but on the flipside he makes good use of his unusual Seattle locations, whether it be the converted gasworks that serve as a public park (and, in the film, a paintball locale), or the attractive Queen Anne scene that opens the film. He's also generous with his actors, giving his adult cast members moments to shine, too: Allison Janney, Larry Miller and Daryl Mitchell (as the no-bullshit English teacher) are particularly good.
Inevitable posthumous postscript: It's strange to see Heath Ledger onscreen in the immediate aftermath of his death, particularly since this film, his first in the US, presumably felt like the culmination of a young man's acting dream. I remember looking the actor up on the IMDB after seeing this film on its original release as I was curious to see an Australian in a Hollywood production; he's charming here but it wasn't until Monster's Ball (2001) that his acting talent first made a real impression.