Check out these tips from Marie Claire about how to dress for the job you want:
Promotion vs. Demotion
Tailored shirts with stretch—fitted looks more feminine
Express your personality through shoes—an element of style you can have fun with. Have your tailor put a hook-and-eye inside the bust of your button-down to keep your bra hidden
Linen—no matter how gorgeous or expensive, by the end of the day, it's a wrinkled mess. Camisoles, spandex, and cropped tops. These are for weekends only. Wearing bright colors—you'll stand out at the Stock Exchange, and not in a good way.
THE GOAL: "Like their male colleagues, women need great-looking go-to suits and several pairs of killer classic shoes."
THE MUST-HAVES: "Three good suits—black, gray, and brown—off the rack that a tailor can make into great suits. Pay special attention to fit, fabric, and sleeve-cuff length: When your arm is straight down, the cuff should stop between your wrist bone and the top of your hand. And a quality watch—nothing too flashy."
DRESS FOR SUCCESS: "Get measured by a tailor, and then seek out designers who cut for your body—Tahari works well for petite frames like mine. Since your work wardrobe doesn't have to be this season, scour the outlets."
FINISH THE LOOK: "Keep makeup simple and natural. I usually just wear a watch, an elegant necklace, and pearl studs—no big statement pieces. You want people to notice you, not your jewelry."
 Art vs. Tart

Search flea markets, vintage and thrift shops, and Mom's—and Grandma's!—attic and jewelry box
Have a go-to LBD you can dress up or down—mine's an '80s Alaïa.  As Coco Chanel decreed, when you're all finished getting dressed, take one thing off.  Wear metallic shoes—they function like neutrals but are more interesting than black.
DON'TS: Being scared of prints, or mixing prints; in the art world, eclectic is good. Avoiding the '70s. I love that era's flair—it's such a distinct style reference. Copying a look exactly—you have to make it your own, organically.
HAVES: "Bold prints, oversize belts, statement accessories. Something that expresses your imagination."
THE GOAL: "When we're trying to recruit important or upcoming artists, it's crucial to represent the gallery. Of course, no one shows up in an avant-garde tutu—it's still a job, not a fashion show."
THE MUST-HAVES: "Bold prints, oversize belts, statement accessories. Something that expresses your imagination."
DRESS FOR SUCCESS: "I have hundreds of dresses and tons of shoes, and every day I look forward to putting together my outfit. I play around with different colors and textures just like a painter does. If you have fun getting dressed, it will show in your outfit."
FINISH THE LOOK: "I wear a lot of jewelry—like, four to six rings at a time. And I love a retro feel, so I work that in with bags and shoes.
Sale vs. Fail
Constant maintenance of shoes, manicure, roots (if you color your hair). Fitted, not tight, silhouettes; conservative length and shapes for skirts and pants (you can sell palazzos, but not wear them!). Jackets in striking colors.
Low-cut or see-through blouses, booty- licious pants or minis. Visible bra straps or thong (obviously!). Open-toed, strappy  sandals or stilettos—they look silly with a hard hat.
THE GOAL: "If you're showing people beautiful properties all day, aesthetics are obviously important. Your clothes signal to clients that they can trust your taste. That said, real-estate development is so male-dominated that women have to work harder to be taken seriously. Dress in a way that's distracting and you become easy to dismiss."
THE MUST-HAVES: "A charcoal, black, or navy suit with a single pop of color—it's classic, with a twist. I'm an urban nomad, chasing taxis and navigating construction sites, so my shoes have to hold up. I live in these black Louboutins because they're not too high. And as I work 12-plus-hour days, I always slip on the Oscar de la Renta flats between appointments."
DRESS FOR SUCCESS: "When you're starting out and don't have a lot to spend, invest in a few fantastic designer pieces you can mix and match. With a starter suit from maybe Theory in charcoal gray or black—and matching skirt and pants for more mileage—you can still afford to go a little crazy with camisoles and colorful accessories from H&M."