They usually come 1-2 at a time, certain areas can have up to 5 Novices at a time, with Tarantulas, a Dark Monk, and very often with one or two Witches. If you are a free account user and want look as if wearing a premium outfit, just use the Creature Illusion spell.
Knights just hit with weapon, pally/mages shoot with rod/wand or distance weapon. Sometimes HMM or even LMM can help loads. Summoning a Fire Elemental or a Demon Skeleton will help alot if you are low level mage.