You can measure a skirt by placing it on a flat surface, such as a table, and using a measuring tape of some sort. You can also measure certain parts of your body to figure out which skirt size will fit you the best. Making these measurements is easy, and well worth your time.
Sari Wrap Skirts: How To Measure Yourself – Darn Good Yarn
How to Measure a Wool Kilted Skirt, Kilt Measuring Guide
Getting your measurements for a skirt - How to know what size is
School's dress code policy requires students to get on their knees
Circle Skirt Calculator & Formula - No Maths Required!
How to Measure a Skirt?
How to Take Garment Measurements of Skirts
Measurement Guide for Women's Tops, Dresses, and Skirts
Q&A: How Should I Measure for a Bedskirt?
5 out of 4 Skirt Measuring and Fitting Guide for any type of skirt
How to : Draft a fit and flare skirt — In the Folds