As soon as I started the game I started grinding, I didn't even save the princess till my group of 2 Fighters, 1 Thief, 1 Red Mage were all level 10 or so. From then on I sailed through everything. At every new town I visit I do at least an hour of exp grinding. I only have earth and fire crystals and already I have so much gil I cannot spend it all. If you go into the right dungeons there's chest after chest full of gil, also.