By StyleWatch
Updated October 21, 2009 05:06 PM

Stefanie Keenan/WireImage

Casual never looked as chic as it did at Hollywood’s Chateau Marmont last night, where stars like Rachel Bilson, Mandy Moore and Lauren Conrad slipped into their best L.A.-cool fashions in celebration of Madewell’s Fall Denim Tour with Lucky magazine. And for Bilson, whose mom, spiritualist Janice Bilson, made a special appearance reading tarot cards for the superstar guests, style has always been in the cards. “I really look up to a lot of my peers and how they dress,” Rachel, who was wearing a Madewell dotted tank, told PEOPLE of how she picks up style tips. “I love to admire other people.” And in a town filled with famous fashionistas, there’s plenty of inspiration to be had. “Ashley Olsen I think is great, Diane Kruger, Sienna Miller — all those people obviously have good style, so it’s nice to see that around you. Your peers surround you, and they all look good, so that’s great.” –Reporting by Pearl Barraclough