Easy Way to Level Up
After you seal the keyhole in Hollow Bastion go to Olympus Coliseum and do all of the tournaments you haven't done. When you get the Hades Cup and get to pick the Rock Titan to battle. At the beginning cast aero so that you get more experience points. When you get to above level 80 beat Ice Titan in the Gold Match. If he is still difficult then continue to level-up. After you defeat him go and battle other optional bosses such as Phantom in Neverland at the clocktower, or Kurt Zisa in Agrabah by talking to the magic carpet in Aladdin's house. When they are all defeated battle the most difficult enemy Sephiroth. It will take multiple tries. He will give you enough experience points to get a level-up. If you still need experience points then either battle Sephiroth again or Rock titan.
Added by: Guest Jun 5th 2011, ID#33637