Do you have mighty guard with quistis? If so, use it at the start of the battle. How many Dino bones do you have? If you have enough, refine them into 100 quakes per party member and junction them to Elem-Def. This way you'll absord the damage from Adels quake spell. Also, Leviathans recover and Alexanders Revive abilities are incredibly useful and they'll stay useful 'till the end of the game. Use them. I'd also use aura on some characters. Irvines AP ammo works wonders if I remember correctly.

Also, if you don't understand the junction system you're screwed. Take the time to go over the basic in game tutorials if you must.