One good technique of astral projection is the one developed by Robert Monroe from the Monroe Institute. This technique was studied and tested on many individuals at his institute to induce a powerful form of Out of Body Experience and consciousness. Robert in a way was a patriot on the western arts of this technique (OBE) using science of the mind to better understand consciousness.
He brought more understanding of OBE consciousness theories to the world and dedicated most of his life to understanding and studying these other levels of consciousness.
Part of how his Astral Projection technique works in the video below is by better understanding of the different layers of sleep patterns and consciousness.
Video Above – Step by step video by Robert Monroe on inducing a Out of Body Experience (Astral Projection).