(credit goes to Player Zzell for this terrific tailoring guide)
Since I’m often asked, I’m going to outline where I farmed for the materials needed to get through the ranks of tailoring. Since armour scraps will always drop in excess, I’ll focus on the fabrics. To obtain ranks, you must buy them from the tailoring master in Greenmont, Legendary Garden, with business currency. I do not recommend buying handbooks since they don’t give extra currency when used.
To get from primary rank to intermediate you need to craft 55 grenadine gloves, which translates to 440 grenadine or 22 stacks of 20. My favourite spot to farm grenadine is south of Messa Camp, in the spot indicated below. Here you can kill level 7 goblins, which drop grenadine frequently. Higher level players are recommended to kill Waterby Mobs in Waterby (South of Greemmont).
2,300 business currency is needed to get from intermediate to advanced rank. This requires 46 Quality Cotton Gloves (23 stacks of 20 Cotton). The best place to farm Cotton is in the Old Oak Mine at the most northern part of Tear Coast, in the area shown below.
To get to professional rank, you need to make 10,000 business currency. Although this sounds like a lot, each Worsted Wool Cloak gives 250 business currency. This means you need 28 stacks of 20 Wool. To get Wool you can kill indigo raiders in the Whispering Islands, the location is shown below. Beware, you also need to buy a handbook from the Tailor Master in Greenmont for 3,750 currency. This is to allow you to craft professional level gear. You need an extra 11 stacks of wool for this.
The final stretch requires 44,000 business currency. Although, again, this sounds like a lot, it turns out that the best source for Moire Cloth is also the best way to grind for XP in the Great Desert when the quest chain drys up. These are the elite monsters in the south of the desert, near the entrance of the Sinskaald Rift. To get 44,000 business currency you need to craft with 29 stacks of Moire Cloth.
Congratulations! You are now a Master Rank Tailor!