"I like to say that every day is showtime," says Los Angeles public relations guru Harris Shepard. Bosses we spoke with around the country agree: The trend is to look "pulled together" (a phrase that came up again and again). Choose the more tailored option—the pants, not the capris; the shirtdress, not the sundress. A no-fail rule from designer Liz Lange: "Dress like the women execs at your company." And if they wear hose, so should you (sorry!).

"You never know who you’ll run into," says Erin McPherson, VP of business development for Yahoo! “I learned this the hard way, being in old jeans and Converse when I got an e-mail that one of our biggest media partners was down the hall and would I please step in?” For casual Fridays in corporate-y places, follow the current guidelines. "We still expect employees to dress appropriately for meetings, even on Fridays," says Audrey Boone Tillman, an executive VP at Aflac. Jeans OK at the office? Wear dark-rinse, rip-free styles.

Perfection is not the goal; who can manage that every day? Think clean and fresh—sheer foundation (if any), mascara, and neutral liner and lipstick (more professional than gloss). If you wear blush, says Lynn Goldenberg, The Body Shop’s director of benefits, "blend well so you don't look like you just came down from a mountain!" For hair, the idea's neat but not fussed with.

Think a cut, a color or an accessory you wear regularly. Individual style gives you an edge at any job. "In creative fields, looking professional means making a statement about yourself," says advertising mogul Mary Baglivo, CEO of Saatchi & Saatchi, New York.

Don’t dress sexy. Or even suggestively. No low necklines, high hemlines, too-tight anything or stomach exposure. The last thing you want is to look like you don't belong.