Heres a quick tip to upgrading your characters in FF13. On chapter 11 there is one are before you get to Vanille's Eidlon where a behemoth is fighting a Megistotherian. You should start the fight with a given preemptive strike. In your party you should have Lightning, Fang and Sazh and use the Cereberus, Relentless Assault and Strike Team. Attack the behemoth first and keep him in the air, it should take no time and the use your magic to keep the stagger chain up. Use commando to keep him in the air and then wail on him. After that the Megistotherian is just clean up. An easy 6600 CP. Travel backward and there will be a lone behemoth, get a preemptive and its an easy 4400 CP. Across the plain is a pack of Megistotherians and an easy preemptive will get you 3920 CP. Keep the cycle going till you've had your fill.