As Dps, there are only couple things you need to worry about:
1/Interrupt the Flare cast of BLM when the ground turns red and Holy cast of the WHM when the grounds turn dark blue. One hit from either if them can put the group in a DEADLY serious situation.
2/Stay away from Mid and stick to the Side. Their triangle shape combo attack can one shot any Caster DPS and 90% health of any Melee DPS.
3/Leave the BLM and WHM as the last ones to weaken or kill for easier time to interrupt them.
4/Do not kill ANY of the Moggles before the King has only 10% health left. Any pre-mature kill before the last phase means WIPE.
5/When all the Moggles (inclduing the Kings) has 10% health left, KILL all of them within 10sec or the party will be wiped.
6/Stack at the middle when the last phase transition (After 2 reviving from the King), when he cast Meteor, for an AOE heal.
That is all you need to worry as DPser.