in this guide we get you from 20-40 my way(may not be best but best i know of)
for the fighters:
if you can sign up for catacombs, grab yourself a pole, and swing away
mystic class:
i like to hang around outside dion at the east gate on the right side of the road with the eye balls and bears and archers
be there till like i'm 25 or something then i search around for another place, eg; breka stronghold, ect ect.
for fighters again cata if possible if not i go to orc barrack. same like cata but little bit harder. can be there untill well into the 30s if need be
then same with mystic breka stronghold, ect ect.
+all of the above:
kama raids palaka at 36 don't forget to do that one(not recommended for mystices though)
then back to the same old same old again untill....
well i like to level to 40 then buy all my quests but that's just me
the kamaels have only 1 quest at level 39 takes like 15 minutes and their done(sweeeet!!!)
other than that enjoy. hope this have been a good help to you. cya around