One of the easiest ways to creating a waistband for a skirt or a pair of pants is to use twill tape.   Twill tape is a  narrow twill woven ribbon that is mainly used in reinforcing stress areas of your garment and is very durable.  In this case, twill tape is used in order to create a sturdy but soft casing for the waistband.  Professor Pincushion demonstrates how to sew in the twill tape in order to create a clean looking waistband for your project.   This same technique can also be used with satin ribbon if you want to use a particular color.