One subset of literature that might help (and seems unmentioned elsewhere) is lucid dreaming.

Lucid dreaming techniques are:

-- fairly high percentage payoff

-- consistent with your overall purposes

-- consistent with your specific purpose

This is a very cheap and fairly credible book.

There's a lot of mysticism and weirdness around lucid dreaming, but the core techniques are pretty straightforward and empirically validated.

If you want a script on this, I'm happy to offer some of my own. Just DM because they're not approp for this sub.