If you think you've got to wear a floor-length gown or cocktail dress to a formal event, you're wrong. Borrow from women like Marlene Deitrich, Angelina Jolie and Mary Kate Olsen and opt for a dressy pantsuit instead. It's important you pay attention to fit and fabric when you're going formal with a pantsuit. With a little know-how you'll be a head turner and stand out from the more traditionally dressed pack.
Pick your suit. A formal pantsuit is a lot different from one you'd wear to the office. Pin stripes are a big no-no. Make sure the suit is tailored if you've bought it off the rack. A suit should be solid navy, black, white or cream. The fabric should drape well, which means it shouldn't cling to your body. A pantsuit in silk is ideal for this. If you opt for more structure, pick a high quality crepe fabric and forgo skinny pants. Make them wide or straight leg.
For a formal occasion, a collared button down shirt is too casual. Try a simple camisole in a feminine fabric like silk or chiffon. The top should be in a complementary, or even the same, color as your suit. You want this to be as streamlined and as simple as possible to pull off formal sophistication.
Put on a pair of heels. Because this look is androgynous, you want to do what you can to femme it up -- that means wearing heels. The size of the heel doesn't matter, but your pants should be tailored to the right length. The hem should graze the bottom of your heel. Stay away from chunky shapes and stick to an almond or pointed toe, which is streamlined and chic. An almond toe is slightly more round than a pointed-toe shoe, but still narrows down at the toe in a similar way the pointed-toe shoe does.
Choose your jewelry carefully. To play with the notion of masculine dressing for women, you've got to be careful about your accessories. You have two options: wear one statement-making piece that packs bling like a necklace, cocktail ring or pair of drop earrings; or go delicate all the way. A thin, delicate long gold chain or a pair of diamond studs paired with thin bangles will give you the feminine look you're going for.