Keep the skirt close to the body, like the Helmut Lang in the top photo.
Make sure to show some leg, either with a slit or a sheer overlay: BCBG Runway, Marc Jacobs and Pucci.
A wide leg silk pajama pant–which billows when you walk– is much sexier than a full skirted maxi, especially if you’re petite or full figured: (Dries Van Notten and Haider Ackermann. ). Done correctly, it’s also a stunning evening look. All images from Style.com