Once you are far enough along, skeleton surprise is a great way to grind it, they mob you, and hit frequently, without hitting so hard as to be too dangerous (careful though, you put your back to a wall they WILL kill you)

You could do something similar at a greydwarf spawner, you get the same experience per hit, you just need things that hit quickly, and lots of them :D


Also, make sure your well rested, you gain more XP when you are