If you want to make gil, try to look for 'untapped markets'. If there's a huge stack of items waiting to sell and they barely sell 1-2 a day (or even worse, a week) take that as a hint to look elsewhere. Low level furniture, specialty foods/potions, leveling gear, base mats, glamours, and some desynth items can really turn a huge profit. As another tip, if you're selling materials that ONLY drop from raids/dungeons/treasure hunts (like orchestrion rolls, glamour mats, etc) don't be afraid to let some items sit on your retainer for a while. My saying is, 'if it sold at that price before, it'll sell at that price again'. (Except when they sometimes make the material available much easier in the next patch)