I find this particularly useful on a lvl 60 character, as you can simply go afk and let your skill rise :)

Step 1 - Fly to Netherguard Keep, Blasted Lands.
Step 2 - Travel to 42,30ish where you will find mobs of humanoids. One of the mobs is called a "Servant of Sevine".
Step 3 - Clear your way to the servant, and agro the servant.
Step 4 - Kite this mob back to netherguard keep, and move it into the southern tower.

Here you must lose agro, and let the elite guards inside the keep tank the mob. Once you have lost agro, you are free to hit the mob, and go afk whilst your skill rises. If you are familiar with the quest involving these mobs, then you will know that you have to cog a crystal for the mob to die. Obviously there crystal is not cogged, and so the mob stays on 1% until a GM decides to despawn it :) (which usually takes 24hrs+ due to the obscure locale.) I'm sure you could pull the mob elsewhere for horde, although I am unfamiliar with the horde camps in that area. I would imagine you could do the same thing by kiting the mob to the horde camp in the south of the Swamp of Sorrows.