The Grinding Method:
rappelz-item.com/tag/level/">level 1-20 : Basically you'll be stuck on Trainee Island till about level 13 pre epic 3. Could be 15 or 16 now with epic3. Basically i won't recommend you using a lightbow as of now, because it'll only hinder your leveling speed. You will want to gain levels as much as possible because thats where it starts becoming fun.
level 21-35 : Just do all your quests in the 3 towns, and it should take you to at least 30+ with Epic3. If you just want to grind, i would recommend grinding on turtles for their slow movement speed. Also, be sure to enchant/upgrade your bow as soon as possible, you need not max your armour for reasons in which i will explain later.
level 35-45 : Pre epic 3, i didn't really have a choice but to grind till almost level 40 on the lafutels in Laksy near ivory tower, but with the inclusion of the Moonlight Dungeon, i would recommend going there to level, reason being, Energy charge which is our primary healing skill don't cut it anymore above level 35.