Out of body experience is a state where your conciousness liberate itself from the body, giving you access to the extent of Conciousness itself, or God, or the Goddess to be more precise. As the Goddess also represent Maya or the extent of the world and universe.
In an out of body experience, I think you are experiencing a liberation into oneself, instead of a liberation from the body. From a Kashmir Shavisnism perspective we exist inside Conciousness, we are a tiny crystal in this fractal of Conciousness.
You can reach obe from yoga nidra or from dream yoga which makes the practice of obe even more interesting in my own process. When the body is in deep sleep if the mind retain awareness you can decided to travel outside the body.
In the technic illustrated by Rober Monroe, you can visualize a point in front of you and then switch that focus from 6 feet in front of you to 6 feet on top of you. There seems to be a focus point or even a chakra at that place that would help with the separation of the mind and body. But it might also simply be a good point of concentration which helps with the process.
Robert Monroe is the only author I've read about obe at the moment and he has a clear pragmatic approach to the process.