Unlock EX New Game
When you beat the game once with either the Toki or Towa ending, you will be given the option to save at the end. This will also update your system data. At the title screen, select New Game to find an option for EX New Game. This will let you carry over the learned Skills, Gifts, GP, and Krone from any save of your choosing, not necessarily the one from when you beat the game.
Unlock Special Ending
On an EX New Game, balance the Love evenly between Toki and Towa and beat the game to get a special ending.