I was just going to come here and say that no matter what I did I could not get 10 torches (and most times wondered how I ever got the intial 4) until I grouped with a hunter and got the speed buff.
So.. summary of tips.
- go to video settings and turn up shadow detail (game menu > options > graphics > right side under effects max out shadow quality and particle density)
- do this in either ironforge or exodar, and with minimal people around (i.e. middle of night or early morning)
- have camera pointed straight at ground and scroll it back as far as it will go (/console cameraDistanceMax 50 and game menu > interface > camera > right side on the camera following style set to "only horizontal when moving")
- toss torch (stand a bit away from the bonfire) and follow the shadow
- stay just ahead of shadow, and turn around just before torch lands. you will always have to go the other way on re-toss. Don't stop running ever till you get to 10.
- Group with a hunter and get speed buff, or use swiftness potion or (someone said but not sure) mount up when you toss the torch initially
Good luck all (and to everyone that posts how amazingly easy this is, stop the egotistical bullcrap bragging cuz we all know its not)