Metal Slimes are a pain in the butt! I hated that quest when you have to kill three of them with that lethal spear move(dunno what it is called in english^^), but they sure give a hella lot XP. Somewhat offtopic, but could somebody tell me how you unlock all the "advanced classes"?? I have swordmage and gladiator but I can't find the rest of 'em...
(hayp17) ok, when i got to that point in the game i was about thoes levels but i had 4 characters (me-warrior, a gladiator, a priest, and a paladin) so in summary, metal slash or just hit them with what you got. You know where to find metal medleys? thoes have 3x as much exp. The other solution is to just train up against powerful monsters just around the plain by gittingham palace.
(purEvil) Ok, in alltrades abbey straight when you walk in just after where you'd turn right to go to the inn theres (still straight on) theres a guy dressed like a muskateer. If you complete his quest you open the vocation(class) of the armamentalist.
If you want a ranger then as your about to go into the cave (which is on your accent to Zere rocks) there are two people who are standing out side the cave. If you complete their quest then you can become a ranger.
The last i'm gonna talk about is in Gleeba. Right at the top theres a fountain (which you slide down into the queens spar place) an there is a man behind it. If you complete his quest he will open up the vocation of a paladin.