First find a piece of patterned paper you like and flip it over. Now stamp the top of the jar, here inked up in Memento London Fog, on the back.
Take a pen or pencil and make straight sides on either side of the mouth of the jar. Kick the line on either side at an angle and then an zigzag line below the rim. Making the zigzag uneven will make the gathers and pleats look more realistic.
Cut it out.
Flip it over!
Here it is over the jar. Now just add some twine or ribbon to look like it's holding the "fabric" over the top. Patterned papers are Basic Grey Pyrus.
Hope this is helpful to you! I'm looking forward to making some pretty Christmas-y toppers this way for my jar with Basic Grey Jovial papers, then filling them with fun holiday images, cookies etc!
Have a great day!