I did as a teen. I found the inconsistencies in the resulting dream structure too annoying. I stopped trying deliberately.
Eg, last night I had a dream conversation with Mal of the Serenity on reactor core dynamics. I became aware of the dream when he couldn't explain how part of the ship he was fixing worked. It fell apart when I wanted to figure out how ship cooled itself. My dream state couldn't support that level of control.
I then woke up and realized that thermophotovoltaic or other sort of nuclear electric system would make more sense than a light water reactor, assuming they figured out how to make that be efficient. There's still a bunch of heat to dissipate.
A trick someone taught me to get into a lucid dream state is to 'touch your nose' while in a dream. The action itself is symbolic, so basically any simple command you can remember to do will open up your ability to consciously control your dream.
If you get into the habit of keeping track of your dreams by doing something like keeping a dream journal, sooner or later you'll be able to remember to 'touch your nose' and lucid-dream at will.
I enjoyed experimenting with it for a while several years ago; it can be pretty exhilarating. But ultimately I found I wasn't feeling rested after a night of living a dream life (oddly enough) so I discontinued the practice.
I wrote total Artificial Intellicence. Very short but evolved by itself in super recursive selfmodifying way. I totally understood how it worked, but I knew already I do not when I wake up. So I tried to construct simple images to give me some clue. The image was a tree which branched when stimulated various ways. Sometimes branches joined together -- this was the key property, but sadly do not understand what it means. :-(
I did it a lot as a child but everytime I forced too much to generate things or whatever, I would wake up, ruining my sleep.
It was also a good way to remember some things I could not remember awake. Nowadays I can't sleep much so I stopped.
Eg, last night I had a dream conversation with Mal of the Serenity on reactor core dynamics. I became aware of the dream when he couldn't explain how part of the ship he was fixing worked. It fell apart when I wanted to figure out how ship cooled itself. My dream state couldn't support that level of control.
I then woke up and realized that thermophotovoltaic or other sort of nuclear electric system would make more sense than a light water reactor, assuming they figured out how to make that be efficient. There's still a bunch of heat to dissipate.
I should have just left the dream a dream.