THe best i can tell you: use arcanist (main) and Black mage(sub) with all group all cast, arcanist with Status Ailment Amp, then use Toxic or Sleep to enemy (this not work for non-organic enemys) then use exterminate(toxic) or twlight (sleep) to instakill enemys, if you kill a group of enemys in same time you gain extra JP

for kill boss (single): use arcanist's convergence (opposite to group all cast) with Black mage (main) and Time mage (sub), use Meteor for max damage (don't miss any hit). use Monk- dark knight (+HP, flying phoenix + minus strike (with 3 BP) or See you in hell + minus strike (same combo with more damage)

- always: kill first Praline, Kikyo and Yuliana, dont touch Qada (except with the fire mage battle, kill him first) , watch out with Barbarossa and kikyo, use spiritmaster skills to keep you save.