The intention of a person, how under control their mind is already, their capacity for revelation ("For many are called, but few are chosen" ), all play a part in the shape and direction of an experience. The best thing a person can do is try to go in without preconceptions of what they expect to find and conditions on how they wish things to unfold - spiritual or cultural traditions, narratives, ideas, desires e.g. meditation. It's like the more you expect, the more you reach, the more you fight, the more you work yourself up, all you're doing is making more obstacles for your attention to latch on to and get tangled up in. This is why I don't think psychedelics are useful for meditation - meditation should come prior to psychedelics.
I remember having a clear direct experience of this on DMT. This was probably on my 3rd or 4th experience. The others were profound - my first left me physically trembling in ecstasy - but I remember getting glimpses of this same revelation all along but forgetting it each time or getting too astonished with what I was seeing. What happened was that the direction of attention inverted to "me" and I perceived (without eyes) directly how the entire experience was emanating from "me" whilst simultaneously I was the experience and viewing it also. In the other experiences there were flashes of this revelation; I got the impression the visual element was somehow intertwined with my thoughts and inner emotional state all at once, but then I'd get sucked along with the experience and forget. It's that sensation many people speak of on DMT; a monumental revelation about reality, that you've been here before, it feels familiar, home, righteous, that you are whole and it all this makes sense.. your entire life, life itself, it's all contained in that feeling.. but you can't quite grasp it and forget it as suddenly as it came. There's a lingering nostalgia post-DMT for something profound and beautiful that you can't quite translate down into ordinary awareness.
It made me realise what I'm really searching for is the one point in the Universe that can't be seen but see's all. If you do a little ground work first I think psychedelics can massively accelerate a persons path, and their ultimate raison d'etre is to just be a mirror to help you see yourself, to remember who you are. If you go in expecting things then you get lost in the reflections rather than recognising there is a mirror in front of you.