What mode are you on? Easy. Medium or Proud mode? If easy, get to about 60-70, and get all drive ability's. If medium, get70-80 with all drive ability's and 6 high-potions. If Proud, 80+, Maxed drive ability's, 6 High-Potions, and Ultima-weapon.
If you are below 80 in proud mode, your screwed.