My daugther and I re-styled her shorts that became to tight around her legs. It was here idea and I did the sewing part. You can also do this with long jeans but you have to cut them to short pants first.
You need a piece of lace that’s about 12cm wide and 30 cm long, I bought mine HERE and your shorts
Cut a piece out of your short on both sides, like shown in the picture
With a sewing machine you attach the lace to the pants
With a pin you ruffle the edges
It only takes ten minutes , and the result is great