Your best bet is keep to the Ancient Forest for now or a slightly higher level cap area, if you like, you can also do Prairie Cave MO, or Mission Orders to level up too. You can find those at the entrance of the dungeon at the billboard nearby in Kaslow Plains.
Also try to use WR, or White Ruins dungeon, since it is unlocked at level 20. That is located at the city of Jale, get there by using the teleport of course. Talk to the assassin looking NPC named Kraft, which is by the Quill Book Merchant, literally taking a straight left all the way from the bank in Jale.
If you are more competitive, try Trial Maze or some similar activitives ^.^ If you have any further questions, just ask, there are many veteran players here in forums~<3