Ok, maybe not a million... however I've had a lot of success as a mid-level weaver (25-35) making reasonable gil to afford my crafting and supplying my FC with nice gear.
The secret here is getting into the undyed velveteen market.
Diremite Web: On most worlds diremite web is hard to come by (only banemites (lvl 25-27) in North Shroud reliably drop afaik). Leves in Quarrymill (11) and Uldah (4) reward diremite web as well. This has created a real demand driven market and I find diremite web can sell for 200-800 a pop depending on market saturation.
Undyed Velveteen: Undyed velveteen takes 1 dew yarn (2 diremite webs) and 1 cotton yarn (2 cotton balls). I my world the velveteen sells for 1.5k-2k per pop and HQ sels for 2.5k+. This means I can make money buying the expensive diremite web and selling the velveteen (I sell in lots of 1 exclusively to maximize earnings and maintain inventory of velveteen/dew yarn).
My "optimal" strategy: Rely on farming banemites/leves as much as possible to get "free" diremite web. I also will buy any web I find at a good price (for me usually < 300 gil). I talk to farmers and strike bargains. The cotton is basically free and easy to HQ. I make sure I always have a half dozen velveteen up on the MB at various prices and I make sure when I log off to undercut current prices by a small margin to ensure movement. I don't have to use all my velveteen for sale to cover costs so I can still make nice gear for myself and FC mates.
Happy earning! Share your gil fountains too!
Edited, Aug 26th 2017 4:18pm by Gidono