This bear started off as a commercially made toy. Unfortunately, I always forget to take before pictures! He was actually really cute right out of the package, just a little too new. I wanted him to look a bit worn, and a little less modern, so I figured out a way to "clump" his fur. I first gave him a bit of a trim, just to get the bulk the fur down in places he'd be particularly worn. Be careful- you only want to cut the fuzz, not the fabric!
Then, I spread a tiny bit of tacky glue over patches of the fur. You really want to use almost no glue! Then, I used a wire brush from the hardware store to brush the glue-covered fur before it dried. Brush in several directions, until the fur looks tousled but not unruly. The trick to making this look right is to work in small sections, and think about wear patterns.