Almost everyone who tries to leave the body meets the same wall. You lie there working a method and checking whether it is happening yet. The checking keeps you awake.
A destination ends that struggle. When the mind is busy walking somewhere it loves, it stops watching itself. The crossing happens while your attention is somewhere else.
The doorway gives its travelers such a place: the Island. It is a small island in the inner world, ringed with pale sand. One straight stone path leaves the southern beach and runs beneath lantern-lit trees to a temple at the center. Many travelers walk the same map. When details they never shared turn out to match, it begins to look less like imagination and more like a place.
You reach it as any place of the inner world is reached: first with a sincere imagination. Imagination does not make the Island. It is the door you knock on.
Visit once a day for a minute or three. Close your eyes and stand on the southern shore. Feel the warm sand, hear the water behind you and the birds ahead. Then come back. A little, often, makes the way familiar.
At night, let it be the last thing you hold. Drift down already walking the path, and rest in one sentence: I wake on the Island.