Leather is one of those fantastic materials that can look better with a little age. Sure, brand new leather garments are nice, but sometimes the old beat-up pair of boots or worn leather jacket are just plain cooler. Here are some tips on how to distress leather garments.
Dampen the leather with rubbing alcohol. Placing some rubbing alcohol in a spray bottle is the best way to go. Then spritz the leather so that it is damp. Do not soak the leather, as it will then be harder to work with and take longer to dry.
Crumple the leather. The first thing you are going to do is add unnatural creases and lines to the leather by crumpling it. Don't be bashful here; really work the leather, almost as if you were kneading a bowl of dough.
Sandpaper your leather. Again, this is all about how "distressed" you want your leather. Remember to start slow, as you can always go further, but it's hard to reverse once done. Use a fine to medium sandpaper and go to town on the leather. Rub some places more than others, and leave others still untouched. Think of the leather as a canvas on which you are painting.
Brush your leather with a heavy bristled wire brush. Now that the small distressing is out of the way, it's time to get serious. The wire brush will do a lot to wear the fabric in the desired areas.
Kick the leather around in the soil. (Make sure it's not muddy.) Maybe go to a local rugby pitch if your dirt is a little moist. Kick the garment around until it is nice and dusty (think Indiana Jones' jacket.) Then after a good dusting, pat off the excess.
There is a product sold called "leather balm;" this is an alcohol-based balm with an acrylic. This may be substituted for the first step instead of the spray bottle.