In Final Fantasy 2, an easy way to increase your stats is to make one of your characters a black magic user, and one a white magic user. Now when you enter battle. Have your character that knows black magic cast a spell on the party member of choice for the hp and endurance increase, then when that character can't take another hit without dying, have your black magic user attack him/herself, or the other party member, while the white magic user restores the weak members health. At the end of battle, the possiable increases, are mp, hp, endurance, strength, magic, and the spells used gain points toward increasing in strength.