In case you didn't know, there's a good early game power leveling spot in the World of Final Fantasy. The area is encountered during the early stages of the game. Within just an hour, you can level up your character up until level 30.
Head you way to The Nether Nebula. Before you get to fight the boss of the area in the last room, notice that located in the safe point is a boulder blocking a pathway you are unable to break. In order for you to get through, you have to level up a Copper Gnome Mirage to 10 and unlock its Smash ability. Use the Smash to break the boulder.
Get Yourself Across To The Area. After passing through the boulder, hover yourself across to the next area by unlocking the Flutter ability of the Floating Eye. That area is your destination. In this zone, you can encounter enemies that are much higher level than the rest of the enemies in The Nether Nebula.
Farm Using Wind Elemental Attacks. The enemies in this area are weak against wind element. Therefore, the best thing you should do is stack up your wind elemental attacks and farm them out. If you are planning to get into this zone, it is recommended to get a Cockatrice Mirage that can be found earlier in the game at the Coliseum. You can evolve your Cockatrice into Valefor which deals a great damage of wind element attacks to your enemies.
There's your secret spot in leveling up your characters easily. Every fight in this zone is worth six to ten thousand experience points and three to four hundred Gils plus items drops. It helps you level up even your mirages that are just in your inventory without having the in combat. So if you have tons of low-level mirages in your inventory, this spot is perfect for you.