After completing the game, make a new file for your save data. Access the Extras Menu from the Main Menu and choose New Game +.. You will be able to access the Grade Shop where you can buy extra stuff that affects your next game with the Grade Points you received upon completing the game.

Item	How to unlock
1/2 Experience	10 Grade
2x Critical	30 Grade
2x Damage	30 Grade
2x Experience	90 Grade
2x Gald	70 Grade
2x Item Drops	120 Grade
2x SP	200 Grade
3x SP	1000 Grade
5x Damage	150 Grade
5x Experience	400 Grade
Chain Capacity +1	30 Grade
Chain Capacity +2	250 Grade
Dualize Discount	100 Grade
Expand Inventory	100 Grade
Inherit Arte Usage	50 Grade
Inherit Battle Items	60 Grade
Inherit Books	10 Grade
Inherit Carta Cards	200 Grade
Inherit Eleth Mixer	70 Grade
Inherit Gald	270 Grade
Inherit Herb Bonuses	70 Grade
Inherit Shards	90 Grade
Inherit Skills	2500 Grade
Inherit Stamps	30 Grade
Inherit Titles	30 Grade
Mastery Bonus	20 Grade
Maximum Eleth +500	100 Grade
Maximum HP +1000	150 Grade
Maximum Speed	50 Grade
Skip Childhood	10 Grade
Trade EXP for Gald	50 Grade
Unlock Qualities	50 Grade
Upgrade Eleth Mixer	50 Grade