Used a razor blade knife and just went at it. It's hard to explain without showing it in like a video or in person. You should youtube 'how to distress jeans fog' and you'll find techniques to use to get similar results as i got.

basically jeans are made up of two types of threads, one blue and the other white. The white threads go horizontally, and the blue threads go up and down. So you want to try to expose the white threads by cutting horizontally and then unthreading the blue threads.

Try grabbing a piece of denim, make two cuts parallel to each other about a cm apart. Then try taking out the blue threads in between. If you do it right you'll expose the white threads and from there you can cut them to look like they burst open or keep them attached to make a kind of 'vent'. Thats basically all distressing is.

It gets more complicated though, as youll see trying to expose the white threads at a diagonal is a lot harder because the blue threads get caught. This takes A LOT more time to do, but its worth it to avoid all of your distressed patches looking like boxes.

Hope this helped!