Playing Final Fantasy Tactics: The Ivalice Chronicles again, this time on Tactician difficulty.
It's not really more difficult so much as it simply requires a different playstyle. The key to success in Tactician is to actually use your buffs, debuffs, and CC abilities. Brute forcing with damage (especially in melee where enemies will hit you like a truck) doesn't work as well unless you really grind, likely more than you'd have the patience to grind.