Someone on X just described an awesomely simple way to go out of body: simply practice thinking of yourself in the third person, and you will reach a turning point where it becomes possible to leave your body. Just don't start talking of yourself in the third person when others can hear, or they will think you quite mad...
At least this sounds way easier than the long and arduous manner that the Gateway process describes, and as such, Occam prefers it. I'll have a try with this, to see where it leads, since I had one out of body experience already, even though it was not by design but rather quite spontaneous.