Game Over

Things you will need:
- Exdeath or Gabranth (Exdeath works a lot better)

- CPU Level Cap +100 (As long the opponent is a higher level you won't need this but it helps)

- Set the PSP to your Bonus Day.

- Get all the EXP Icon Boost (Again to Speed up the process)

(Optional) - Get all the other calendar boost items if you'd like to get 40PP,  +3 AP, 2x Gil per battle.

EXP Grinding Rule-set:
- While on the main menu, go to the sub-menu "Data Config"

- Select "Original Rules"

- Choose one of the empty spaces (No Rule) on the "My Rules" section.

- Once you select one of the empty slots (No Rule), choose the "Edit" option.

Now, you'll see a handy amounts of options. We'll have to mess around with them now. (Also only configure the ones i mention, leave the others untouched.)

- Initial Stage Bravery (1000)

- Critical Hit Rate (1000)

- Critical Hit Damage (1000)

- EX Core Appearance Rate (4)

- EX Core Absorption (700)

- EX Force Absorption (0)

- EX Mode Duration (120)

- Wall Rush Damage (200)

- Bravery Bonus (100)

- EX Revenge Duration (10)

Now you save the rule-set and name it whatever you'd like.

From Source : "Now, what this ruleset does is drastically increase the power of Critical hits, so much that even a Level 1 can put a dent in a Level 100's Bravery. Plus, the EX Core appearance is so high, that collecting one will automatically make another appear, and just picking up the EX Core fills out your gauge to go EX. While in EX Mode (which will last for 120 seconds at maximum), you have a higher Critical Hit chance, while the Criticals themselves do a lot of damage. Try for Wall Rush for a lot of extra HP damage to quicken the pace, now that it's at 200%. With the altered Bravery Bonus at -100, you will now start with a maximized Bravery score pretty much allowing you to deal the maximum amount of damage at the outset of battle."
Time for the actual level grinding.

- Go back to the Main Menu

- Select "Battle Mode"

- Select the "Quick Battle 1-on-1" option.

- Choose any character you'd like to level up.

- As your opponent i recommend choosing Exdeath.

Battle Setup:

Stage: Order's Sanctuary

Strength (CPU) : Maximum

Level (CPU) : 100 (Anything that's higher works than your level works)

Type (CPU) : Extreme

Rules : Use the Rule-Set you made.

Judgement : None

Now, just make sure to dodge all of Exdeath's attacks (Don't worry Exdeath is very slow and calm), always go for the "Ex-CORE" and try to finish the battle with your "HP Attack + Ex-BURST". You should finish the battle instantly and get your insane amount of XP but if he's still alive, rinse and repeat.

Tip from source: "The best trick learned with this set-up is to snag a Core, then wait for (EDIT: Exdeath) to attack you. Use EX Revenge to break out of the attack, quickly grab the new EX Core, go EX, and then use an HP Attack+EX Burst on (EDIT: Exdeath) before EX Revenge ends. Rinse and repeat until you win the battle!"

Now make sure to equip any EXP Boost Accessories you have, is not necessary to do so but it speeds up the process.

Of course if you got all the other Calendar Boosts like i mentioned, you'll get a good amount of PP, AP and GIL as well.

Happy Grinding!Source