Archers are one of the easiest class to level up in, I think it can level up anywhere because it has all the elements of the monsters covered except for monster with high level of defense(unless you have thanatos card) and neutral class. The things you need are pots(for hp), grape juices(for sp) and purchase different type of arrows that are available to you. The best way to level in the area you selected is to use the weakness of the monster's element as it would increase the damage towards the monster.
