I used a (H&M $10 linen, drawstring) skirt that I liked to draft a pattern.
I took the top of the skirt measurement x2 to make sure it was at least the same length as my waist circumference. Then I added 2 inches for seams and comfort.
For the length, I measured the lenth of my H&M skirt. Then added 1.5inches (1.25 inch hem and 1/4 inch for folding at top).
For the width of the skirt, I measured my H&M skirt and added an 1 or so for some flare. I like the A-line look so I wanted to make sure my hem was a bit wider than my waist.
I connected the waist line and the hem line and ...voila...my pattern.