To create a gold machine in wow you need 2 characters, a lvl 110 and a new alt.
The level 110 should be a druid with herbalism and mining. (Bonus to have the fastest flying)
Your alt who you are leveling should have alchemy and jewel crafting.
You will then farm the world for the ingredients needed for your alt to craft the stuff.
Find out what sells good on AH that you can craft and BOOM you have a money machine.