Late Game Leveling
[Submitted by: Cheat Masters ]
At the start of the game's 4th disc, head to Urha after gaining the Nautilus Boat following your party's reunion. Using Tolten, you can break the Urhan Seal in the Gongora Mansion's courtyard. This will gain you access to a secret dungeon.
The enemies you encounter there are called Experimental Number 42 plus you will fight them continuously during your time there. These are ratheer tough foes, they pack a heafty punch and can petrify your party easily. If you are above level 35, you will be in good shape to hold your own. The key is to have some anti-petrify skills or gear equipped to combat their deadly attack.
The SP these enemies give up when killed is staggering, and will allow you to level up quickly. There are no level caps here like there is elsewhere in the game, so that makes leveling up in this location over a long period of time up many, many levels a possibility if you have the patience to do so. Just remember to leave the dungeon every so often to heal and save so you don't lose all of that leveling progress!

HP/MP Recovery
Description: Quickly recover your party's HP and MP automatically
How to: Head to a save point and save your game. Now, shut your game off and reload the save file. Your entire party should have full HP and MP.

To heal your party quickly, all you have to do is head to the world map. This works anywhere in the game, as long as you have access to the world map at any given time.

New Game+
To unlock a new game ("New Game+") after the main game, beat the game, save your game after the ending is over, and start over again.