Scissors or seam ripper
So I put the jeans on to mark out where abouts I want the holes and distressing, after that I took off the jeans, important step! And began with the grater to wear away the fabric, then used the scissor to pull out and clip away any of the fibres.
I want to keep the horizontal fibres and pull out the vertical ones.... If that makes sense.... Like the 4th picture.
Enjoy and happy DIY'n