In the movie "Altered States" the character played by William Hurt went down into this "man made" salt tank. There was alot to this movie, but what I remembered was that he wanted to increase his ability to "alter" his mind.
This is a magnificent way to ALTER "your" imagination too.
First, get to a quiet, peaceful room, (don't worry if you don't have a salt tank nearby). Find a place where you can sit comfortably,
Don't do this while driving or operating heavy equipment.
(sorry, couldn't resist)
But seriously, don't do this while tired,
YOU WILL FALL ASLEEP!
I have used a rocking chair in the past, this is good for occupying the body, your mind is what you need for this, not your body.
Now that you have your "imagination tank" ready, go turn off the lights... or clap on, clap off if need be.
Once again, make sure there is "no light what-so-ever" in the room, this is to optimize your efforts.
One more thing before you start,
YOU HAVE TO KEEP YOUR EYES OPEN
Now, intently think on something that has been perplexing you lately.
Within minutes you will have your:
...answer to the perplexing question.
...conclusion to a story.
...memory back from years before. (you may not want this)
...or in my case, excellent book ideas, watch designs, or
Try it out...
Don't blame me if you have an "ALTERED STATES" moment.