As you slay monsters, PVP, and do quests, you gain experience points. After you reach a certain amount of Experience points or EXP/XP, you will level up.
Leveling up unlocks stat points which in-turn gives you the ability to become stronger and wear/wield better armor and weapons.
What places are the best for what level?
- Lv 1-10: Killer Bees, Sheep and Little Fairy (for extra money) (at Darom and Farm
- Lv 10-20: Undead Fisherman at Mendom at night and Goats (west of Rasheeb)
- Lv 20-...: ....
Check the Monsters page for the overview per level, area and Exp.