One ruffle or two? Here's how:
Start by making a pair of pants. Any pair of pants. I have a tutorial here if you need a simple one. Hem the bottoms to your desired length.
You will need four strips of fabric for the double ruffles, or two strips for the single ruffled style.
Each strip should be appx. twice the circumference of the pantleg. Finish the long edges of each strip (use a rolled hem, zig zag stitch, turn them under, let them fray... whatever you like).
Sew the short ends closed so each strip forms a circle.
Using your machine, gather the top edge of each "circle" to ruffle it as shown below. Adjust the gathers until the ruffled strip fits around the pantleg.
Fit the ruffled strip over the pantleg (use the bottom hem of the pantleg as a guide for placement). Distribute the gathers evenly and sew over the gathering stitch to attach the ruffle to the pantleg.
Using pins for accuracy this time, position the next ruffled strip overlapping the first one.
And stitch into place.
(Lisa from Cheerios Underfoot - this pair is yours. Thanks to every who entered the giveaway.)