Faction? well the awnser is simple, go to the 10-20 zone, it will be all over, darkshore/barrens/westfall/the Loch/silverpine, heck even a lil in the 1-10 start zones too, but if ya do the 10-20 zones you may find your tin soon.
For alliance: Elwynn forest-->Westfall is your best choice. Dun morough has too many random spawns...imo.
Just go south of Goldshire, and you should find a kobold cave, Should be 3-4 nodes in there. Then run across the hillside all the way down to redrigde entrance, or close, and keep looking for ores. Come back to the mine once in a while. hope this helps. gl
newb areas, and up to lvl 20 really. If your alliance go to elwynn forest (?) the area right outside of stormwind, where goldshire is. tons in that area, especially around the mines and the hilly areas south of the road.