Kingdom Hearts Message Board  

Leveling up in this game takes a LOT longer than in the second Kingdom Hearts game. I would suggest doing the tournaments in the Collesium if you have not done so already, especially the Hades Cup. Even if you have done that already, try doing it alone and the time trial. You get good items in every tournament for doing all three. Other than that I would say go to later worlds such as end of the world and Hollow Bastion where you get more experience points for defeating enemies. All I can really tell you is it takes a lot of time and patience.