Herbalism - Alchemy = farm volatile life and transmute to volatile air in uldum.
This on my server is: 200 gold for 20 volatile life, but 12-1400 for air since harder to get. (ps you also can buy the volatile life and transmute and still get alot of profit)
Mining and JC
Mine in uldum northwalls from left and right, gives you alot in short while. also 2 nodes with 5 in each spawnpoint on that road and 3 pytite spawnpoints and 4 rich elementium nodes.
Prospect the elementium and get blue gems and make 20+30 recipes for more profit, like 20 dodge+30 stamina or 20 intellect+20 haste, depending witch are highest on youre realm. the green gems(hessinite etc) you make fire prizm each day with and get blue.
Fishing and cooking
Go to uldum and fish and you get fathom eels (gives tankingbuff from cookingrecipe) and sagefish (gives healers 90 stam and 90 spirit) and sell really good, in addisional you also get volatile water to sell.
Run quests for the loremaster and disenchant all rewards you dont need and sell mats ito make more than the actual enchants, specially high lvl quests 80-85 in cata.
Also go to AH and buy up cheap lvl 78 cata gear etc and disenchant and get 3-5 times as much back by selling the mats.
Mysterious fortune cards are really selling good with the correct prize...people get addicted..."just one more card" in the hope of 5000 gold reward.
in my server cinderbloom stack costs 100 gold...farm if you can (recommend vashiir for asharaz veil instead since nobody farming there compared to other lands, then mill them down and sell for 40 gold on ah, link in trade and you are good to go. ps if buying a stack instead for 100 gold it will make you 5 and sold for 40 gold cheap it gives you 100 gold in profit.
Also make the priestbuffscroll, selling for 100 gold each on my realm...and you cant really make something else with the special flowermats.
Yes...its tidious but can give you alot of good stuff and alot of money, the tol vir fragments sell from 1500 gold and up since only gotten in uldum and not often, night elfs tabletscrolls sells for around 450 nand easy to egt..overall...sell fragments, people will always need them for the extra dungeonbuffs and solving pussles...really good gold on this.
If you also have alchemy you cna get the drakerecipe and sell the mountcrafting...and mount if you can.