After you’re done with farming wool, silk is the next material to find. Silk is likely to drop from humanoids between the levels of 32 to 40. One of the hot spots to find Silk cloth is Blackhoof Village, Dustwallow Marsh, it’s a small village filled with mobs that will drop plenty of silk. I recommend circling the place until all your bags are full and fully emptying them out before returning. Below is a map of where to find silk in WoW.
If running through instances is more of your thing then Uldaman, Badlands is for you. The reason why instances are also recommended is because it is usually safer from other players ganking you while you’re farming. Once you’re in the dungeon, no one can disturb your farming progress. Other players’ ganking you is the worst interruption while farming, productivity and efficiency will just go down the drain. Uldaman is a pretty big dungeon and you may get lost a few times but the return is great.