Technique for weathering cloth
Weathering cloth can be quite simple with the proper tools, such as a power sander. You can acheive the worn and tattered look this way.

Because this uses power tools, please use the precautions necessary when doing this. Wearing Goggles and perhaps a face mask is strongly suggested. Small cloth particles fly off. While they won't hurt you, it's not fun to inhale in nor get in your eyes.