Armor and weapon selections
When you are a certain level, you can only wear a particular armor without it decreasing your attack or defense. Usually the weapons you can equip are five levels lower than the said required level. For example, a level 21 weapon can be used at level 16 without it decreasing your attack/defense; or a level 22 armor piece (boots, gloves, chestplate, leggings, helmet/hat) can be equipped at level 16 or 17. While you level up, it is easier to get better weapons and armor as you go (more defense and attack), also making it easier to level.
Go to Dratan if you are at least level 15. Go to Prokion Temple. You can find locations where players have dropped money, or kill ghouls and mummies.
Go to the Boku Daemons with a party and fight them.
Easy pet experience
Get a pet (dragon or horse). Do the quest with Pan Flute or Drake Egg. Get some food for the pet (herbs for life, mining stones for starving, and energy for sympathy). Battle a monster with a white or yellow name without any weapons. Every time you hit, your pet's experience will increase.
Wear armor or weapons without their requirements
To wear armor that you do not have requirements for
(for example, the level), drag it as you would do to a normal
armor or weapon. You must have at least level 1 with at least
Strategy guides from GameFAQs