You have to keep your sanity as well as know how to distance yourself from it while still holding onto the reins tightly. That is a very difficult thing to do but I'm learning.
I didn't go to film school so my learning was done out in public and showed up on the screen.
Next Article
But the mechanics of learning to 'throw your voice' are pretty simple. Anyone with a tongue an upper palate teeth and a normal speaking voice can learn ventriloquism.