Sometimes she even hits Target, saying, "A great top by Mossimo you might pair with a really great sweater and a pair of Chip & Pepper jeans.",

Stevens always mixes designer brands with off-the-rack finds.

"I thought this would be nice for the kickoff carnival just because I thought it had a festive feel to it," Stevens says, adjusting a striped, zip-up sweater in pinks, oranges, blues and greens over a tomato-colored tank top. She pins a pleated denim miniskirt at the waist of the women's dress form, pulling it tight at the hips.

A pair of red Marc Jacobs flats with what Stevens calls "cherries" on top are placed at the foot of the dress form to complete the look that will be worn this season by Marissa, who's still reeling from her break-up with Ryan, played by McKenzie. Marissa is played by Barton, 18.

"She's the fashion icon of the moment for this generation, ... that fresh-faced ingenue that never looks like she's trying too hard, but she's always perfectly put together," says Gina La Morte, a stylist for Teen People magazine and founder of Style Doctor, an online fashion resource for girls.

Last season, Barton's character was all about clean silhouettes and Chanel handbags, a combo that signals status with virtually no effort. Her skirts get longer this year, and she wears a few tweed hats and pearls. But otherwise, designers decided, why fix what obviously has been working?

The sway Barton has with fashion-obsessed teens amazes even Stevens.

"If Mischa wears it, I can't even tell you what happens," she says, recalling the night that Barton wore a set of beads to the Teen Choice Awards. Once word got out, the store where she bought the beads couldn't keep up with demand. "It's just amazing how that happens."

In contrast to Barton's character is best friend Summer, played by Bilson, 23. Summer's style was still a work in progress at the end of last season. But this season she gets a new wardrobe: peasant blouses and skirts, open-weave ponchos and lots of beads.

"She wears clothes so well that it's been fun to try to mix and match her, like in long peasant skirts and a very modern belt," Stevens says. "There's still a little beachy side to her, though. She's just kind of evolved."

And while the boys may not be as fashion forward as the girls, at least one will be giving more attention to his look. Seth, the lovable slacker played by Brody, 24, returns from a sailing adventure a new man. He will be sporting Vans slip-ons, trousers and long-sleeved shirts in solids and stripes. That more serious, grown-up style replaces the Penguin shirts that served as his trademark in the first season and which Brody adopted off-screen as well.