Mastering classes is crucial for unlocking powerful skills and spells. The key to efficient class leveling is understanding the 'battle count' system. Classes level up not by experience points, but by the number of battles fought. However, there's a catch: each area has a 'class experience cap' based on the strength of the monsters. If you fight monsters that are too weak for the area, you won't gain class experience. To level classes efficiently, always fight in the strongest area you can comfortably manage. For early classes, the areas around Dharma Temple are good. Later, the bonus dungeons unlocked by Monster Park fragments or the final dungeon areas are ideal. Don't be afraid to switch classes frequently to learn a wide array of skills, as learned skills are permanent. Prioritize mastering basic classes to unlock advanced ones as quickly as possible.
