Few months back, I cut my old jeans and made it into a frayed pants! As the jeans were a little loose on me, I had to wear a belt with it. But still, I kinda like how I give new life to my old jeans. ^-^
No sewing is required. Just cut away! Get a pair of your favourite shorts cutting and trace the outline on the old jeans accordingly and cut away! After a few washes, the frays will come out beautifully and naturally by itself. You can even bring it up to the next level by bleaching it or dip-dying it.
PS: If you don’t have any old jeans, you can try looking for cheap ones at Song and Song Fashion or Salvation Army!