Advice #next:
0-40: Buy from wrestling instructor
40-60: Kill zombies and skeletons in Haven
60-70: Kill lizardmen
70+: Golem, shadow elemental, ogre lords, summoned demons or earth ele's, etc.
What I'm currently doing for 70+ is using my spellweaving to collect an arctic ogre lord. Then I set the frosted badness on a poison badness, like a rotting corpse. Then I punch the corpse. I've also done this with shadow iron elementals. I've trained my wrestling while people train their pets. You just have to remember to take a 2 minute pause every 10 minutes to let the elemental heal.
But the easiest and probably fastest way of training high wrestling is via golems. I just don't think it's any fun.