Kara DioGuardi in O, The Oprah Magazine

Kara DioGuardi: Uncommon Color Mixes
Tone up! Two or more shades, inventively combined, make for a brighter outlook.

The color wheel turns again as designers go in for daring juxtapositions of rich, sophisticated hues like violet and saffron (blouse, Club Monaco, $119; skirt, J.Crew, $78). To make a mix like this work, use tones that are the same level of intensity; it also helps to separate them (grosgrain ribbon worn as belt, Mokuba). The one-bare-shoulder look highlights a part of the anatomy that's slow to age (hooray!). Kara DioGuardi, who needs interesting tops as a judge for Fox's iconic music show American Idol—she's mostly seen from the waist up—says this style makes her feel "sexy but still strong." Edgy quartz, onyx, and sapphire jewelry (Iradj Moini) and glittery-strapped nude shoes (Lanvin) give this Grammy-nominated composer (for everyone from Gwen Stefani to Celine Dion) a touch of rocker chic.
Kristin Cavallari

Kristin Cavallari: Feminine Frills
French dressing with a '60s feeling. Très soigné.

Making the French connection can be as uncomplicated as layering a black sweater with a white blouse or as haute couture as runway looks evoking Yves Saint Laurent's celebrated designs for Belle de Jour. In that classic 1967 film, Catherine Deneuve plays an icy wife with something to hide—a secret life as a prostitute—and her exquisite clothes are the perfect fusion of demure and sensuous. So is this dress, combining opaque with sheer, sleekness with ruffled touches (Ralph Lauren Blue Label, $798). "It's sexy without being in-your-face—it has class," says Kristin Cavallari, an alum of MTV's teenage Laguna Beach and now starring in its 20-something spin-off, The Hills. Kristin also has two movies coming up: Wild Cherry, a high school comedy with Rumer Willis, and Van Wilder: Freshman Year, where she plays an ROTC girl. 

Shoes, Charles David.
NeNe Leakes in O, The Oprah Magazine

NeNe Leakes: The Color Purple
Pile on a few different tones, or wear just one plum piece.

It's a royal color, and the fall fashion shows have shown that it's hip again. One of the most colorful characters on Bravo's hit docudrama The Real Housewives of Atlanta, Nene Leakes adores this Empire-waist shift dress (Tory Burch, $395), and at a statuesque 511, she can definitely carry off the cashmere cape (Ralph Lauren Blue Label, $398). "It's business yet playful," she says. "Snatch it from your closet, throw it on, and you look fly." Although she still fumes about the gossip surrounding Housewives (get the dish in her new book, Never Make the Same Mistake Twice), Nene relishes the way the show let her "put myself out there on a great platform for the world to see." 

Cuff, Ted Rossi. Bracelet, Ben-Amun by Isaac Manevitz. Ring, Russell Jones. Shoes, Camilla Skovgaard London.
Jackie Warner

Jackie Warner: Heavy Metal
From studded cuffs to embellished dresses, it's time to shine.

There should have been a metal detector on fall runways, judging from the steely gleam in designers' eyes. You can play the trend tough or work it less aggressively (silver nail polish might be enough). This shimmering lamé jersey dress, with lavishly jeweled borders (Sue Wong, $374) and shaggy silver-threaded coat (Diane von Furstenberg, $895) are fancier than Work Out star Jackie Warner is accustomed to: Both in the gym (building on the success of Work Out, she's now developing a new fitness show for Bravo) and on the street, her taste is on the edgy side. Jackie's supertoned legs are perfect for short skirts, and she's certainly into black ("I say I'll buy color, but I never do"). The blackened sterling silver ring (Stephen Webster) is right in sync with her style: "I always add something punk or rock 'n' roll," she says. 

Shoes, Jimmy Choo.
Claudia Jordan in O, The Oprah Magazine

Claudia Jordan: Shapely Suits
Unmatched but matchless: Elegant pieces with '40s flair define the body.

If you've drooled over the glamorous suits in old movies, you'll be thrilled by the vintage influence in today's tailoring. What's modern is the mix of neutrals: a charcoal-and-black jacket (DKNY, $245) with shoulder emphasis and a nipped-in waist, black pencil skirt (Ann Taylor, $110), and faux-fur stole (Adrienne Landau). Claudia Jordan is crazy about suits (wearing them was a highlight of being on Donald Trump's survive-or-be-fired show The Celebrity Apprentice). "Structure is sexy," she says. "It looks sharp and smart and expensive, even if it's not." Until recently a case-wielding model on Deal or No Deal, Claudia is cohosting this year's Miss Universe pageant (NBC, August 23). "A lot of girls look up to whoever they see on TV," she says. "It's important to me to be classy." 

Hair feather, M&J Trimming. Grosgrain ribbon (worn as belt), Mokuba. Shoes, Chanel.
Trista Sutter in O, The Oprah Magazine

Trista Sutter: Mad for Plaid
Handsome patterns could be a woman's best friend.

Kilts gone wild might be the motto for this season's plaid-layering craze. Get a piece of the menswear action with a single dashing buy, like a tartan peacoat (Tommy Hilfiger, $340), or try multiples: Combine a large, vivid plaid with neutral, smaller-scale motifs, such as these glen plaid trousers (Loft, $80) and tweedy, checked fedora (Christys' Crown Series by Tony Merenda). Trista Sutter (here with daughter Blakesley) loves this outfit's warm, unfussy feel—a snappier alternative to her everyday mom clothes (once the ultimate single girl on ABC's competitive dating shows The Bachelor and The Bachelorette, she now has two children with her husband, Ryan). Her life is less about trends lately: "Paying out the wazoo at high-end boutiques is just not me anymore!" But she'll definitely give plaids a second glance when she's shopping the sale racks. 

Shirt, Ralph Lauren Blue Label, $245.  Shoes, Philosophy di Alberta Ferretti. Shawl, Liz Claiborne New York.
Helen Phillips in O, The Oprah Magazine

Helen Phillips: Brights for Night
Skillful draping and a surprisingly vibrant palette are evening stars.

You almost needed dark glasses at the fall shows—the evening looks were that brilliant. So instead of staying in the black, let yourself be looked at in a dazzling peacock dress (Byron Lars Beauty Mark, $475). Helen Phillips is so ready to be noticed: She lost 140 pounds, going from size 22 to 2, on the seventh season of NBC's weight loss marathon, The Biggest Loser (season eight premieres September 15). "I hadn't worn a dress in eight years," she says (her closet contained 30 pairs of black pants), "but I must say I look hot in this!" Not because it's ultrashort or revealing, though—the elegantly gathered sleeveless bodice and soft, pleated skirt show off her body, but discreetly. Now a motivational speaker ("My message is that you're never too old to change your life"), Helen's self-confidence shines even brighter than her dress: "I feel like nothing can stop me." 

Shoes, Jimmy Choo.
Kim Kardashian in O, The Oprah Magazine

Kim Kardashian: The Power Dress
The new year-round uniform is a sleek dress with detail.

Fast, fresh, and streamlined, the sheath ruled the season. Some of the best featured interesting patterns, like this burgundy silk with a white rose (Elie Tahari, $498). The dress may be very Michelle O., but the short bouclé jacket (DKNY, $395) is more Jackie O (not to mention a useful cover-up for the office). "The higher neckline and longer hem are conservative, but it's fitted to show off my curves," says Kim Kardashian, one of three sisters on E!'s blended-family chronicle Keeping Up with the Kardashians (which documents the lives of her mother, Kris; Kris's husband, Olympic athlete Bruce Jenner; and their kids). The fashion entrepreneur co-owns Dash, a California boutique, with her sisters, and has helped start an online shoe club, ShoeDazzle.com: Every month you get a handpicked pair based on your style preferences (these, ShoeDazzle by Michael Antonio) for only $39. 

Belt, Elie Tahari.

O's Fall Fashion Handbook