What are some useful gambits in this game? Sharky and I are now up to the annoyingly long Sandsea, but at least it's a good place for grinding. Been taking some time to do some hunts and stuff. Bought all currently available gambits, so could use some help deciding on some good ones! I like this game, but I've never been good at it

Character setups:
Vaan: Green Mage, Daggers and Crossbows
Penelo: Tank/Paladin, White Magic, Swords
Balthier: Time Mage, Guns and Hand-Bombs
Fran: Black Mage, Bows and Rods
Basch: Dark Knight, Arcane Magic, Swords, Axes & Hammers, Spears
Ashe: Cleric, White Magic, Staves, Swords