• Gathering (good for when you don't have some serious gil)
  • Crafting (requires you to have some serious gil already)
  • Treasure Maps (need a party)
  • RP'ing and ERP'ing (hosting or attending one but you make more with house rp)
  • Farming old content and selling items on MB or Vendor.
  • Farming new content and selling items on MB or Vendor.
  • Reselling items from beast tribes on MB that are purchased locked behind rep rank.
  • Playing music in one of the HUBs (gil trades are rare for this method from my experience)
  • Doing some Hunts (solo or with a group)
  • Running through all of the Duty Finder all day (slowest and lowest profit earning method)
  • Boosting all classes (one time method which will neat you 2 mil gil)
  • Being a twitch streamer with a decent viewer count tends to neat you millions of gil on the monthly from random trades
That's about it, So just take your pick at what you prefer.