The Lowdown: Sweater dresses can either be a fashionista’s best friend or her worst nightmare. The key? Fit, fit, fit. Ignore the numbers, ladies — cut out the tag if you must — but trust us, a sweater dress that fits properly (skims the body, but doesn’t cling, bunch or gap) is a versatile fall/winter staple you should have in your closet. Almost as important as fit? What you wear with it, and this is where the fun comes in. Wear it with a jacket (dress or denim), sexy boots or fun flats, maybe a fab big necklace or cocktail ring, and go. It’s almost too easy. Here are six designer options we like, courtesy of Bluefly.com (yes, they’re a little more expensive than, say, Forever21, but they’re higher quality AND right now you save 30 bucks on your first order of $150 or more at Bluefly with code AFF30). Oh, and don’t forget — Spanx truly are a girl’s best friend.