I built a high level zon and found that the Decoy skill is great. It prevents you from running into bad guys at close range while walking through the world. Necros can use the same tactics with a clay golem or fire golem. I use clay golem only because fire golem uses lots more mana and I case the clay golem frequently.
I find that this skill is a lifesaver. I cast it ahead of me, into rooms before I enter, or at the edge of the screen. This draws the attention of all of the bad guys nearby so I see them ahead of time at long distance instead of almost running into theml. It saves a lot of wear and tear on my guy.
Thought I let you know about this tactic as it's life saver.