The best tactic is to cast 2 webs in there followed by 3 Firebolts,followed by 2~3 Holy Smites and a Cloudskill... After that all u have to do is stand outside and leech the XP
(Note this is more useful for the Great Hall in level 1 if u have Tactics installed, or for Torgal's minions in the dungeons) Those tactics did wonders for me