When I first started buying my own feminine clothing I also used the size chart in a JC Penney catalog, but I never bought anyting from the catalog itself. I found that the easiest thing was to get an approximate size and then shop in person at a store that has a reasonable return policy, i.e. if it doesn't fit, they let you return it.
To size a skirt, waist size is most crucial for the male figure--if it fits in the waist it will fit in the hips. Bust size is the best guide for tops. Women's sizes and styles are so variable that you can never be sure that a garment fits until you try it on. But that is where the fun begins. 🙂
