Just taking advantages of all the rappelz-item.com/tag/quest/">quests you can early on when you start the game. They are immensely helpful and help you to learn the basics of the game. Rappelz is a game that even we as an R6 find ourselves discovering new things on a regular basis.
When there are no more adequate quests and you find yourself at a loss of what to do for experience in Rappelz, try finding what is called a "DP" or a dungeon party. The levels we would suggest for each dungeon are as follows:
Relics of Arid Moonlight for Levels 30-50. Lost Mines at Levels 45-65. Crystal Valley at Levels 60-85. Palmir Plateau for Levels 80-115. Veiled Island for Levels 115-125. The Sanctuary after Levels 120. Temple Of Ancients after Levels 135.
At any point there are various areas to "solo" which may or may not be more effective based on your playing level. And of course there is "farming." Farming is a term coined due to its monotony referring to the killing of regular field mobs. Killing field mobs for exp is in our experience much inferior to killing in a dungeon with a party or killing "Champion mobs" which are "+" monsters.