In "Erin Brockovich," Julia Roberts showed off her curves to distract men during tough negotiations. But it doesn't matter how great your cleavage looks when it pops out of that little sheer blouse you just bought -- you have to keep it covered when you're going for the dressy and professional look. Same goes for below the waist. Any skirt that ends above the knee is only going to attract ogling stares -- not promotions.
Black, gray and navy are all staples of any professional woman's closet, but they don't have to be the only colors you own. In fact, adding a pop of color here and there allows you to retain your personality and femininity without sacrificing your professional veneer. Inject a little color into your outfit with a bright blouse, colored earrings or even a scarf. Be careful not to overdo it -- leopard print blouses don't exactly scream, "I should be taken seriously."
Your accessories should be modest -- they're there to complement your outfit, not define it. Your shoes should be close-toed and not more than 1 or 2 inches high. One or two rings, a watch and a pin are all dressy and professional, as long as they are modest. Your belt should match your shoes and purse.
Use makeup, but make it conservative and naturalistic -- save any glitter eyeshadow for the weekend. Your nails should always be neat and trimmed. If you wear nail polish, go for conservative, solid colors or a French manicure. If your colors are chipped and cracked, clean and repaint them.