Oxiracetam might improve it.
I've tried a several nootropics (piracetam, modafinil, pramiracetam, aniracetam, choline, sulbutiamine, others) and had varying results.
I took 800mg oxiracetam 3 days in a row, and found that I could visualise maths equations that I had seen on paper but did not yet understand. It was similar to having photographic memory. My head felt like an empty cave with caverns I could explore.
I stopped taking it after the 3rd night, when I heard an imaginary voice say "Good night!" as I was in that fuzzy area between asleep and awake. It spooked me out ("what if i permanently hear voices now?!") and kept me awake a couple hours from fear. In those couple hours I had mild HPPD (tried revising more and the words were wobbling on the paper).
The next day there were no side effects, and have been none since (never taken it again). I have read extensively on all major nootropics communities and posted on several - nobody else seems to have had the negative side effects that I mentioned. I also get the impression that the near-photographic-memory I received was rare too, although I have read one of two posts where people have mentioned it over the last 3 years.
I think both oxiracetam and aniracetam lowered the quality of my sleep too, but have not quantified this.
I no longer take nootropics, except piracetam, which I use as a replacement to alcohol for parties - it makes me extremely social, creative at talking (as if on a lesser form of mdma), able to process three people speaking at once (I cant do two normally (very few people can)), confidence boost. And there is no hangover.
Oxiracetam has not been around long enough for there to be long-term results from human use. Piracetam has, and there are no long term side effects that have been observed.
Previously: Generalizing From One Example
Summary: I do not have visual mental imagery. I want it. How do I get it? What exercises, if any, will help?
In further detail... Here's Francis Galton's Statistics of Mental Imagery paper. I'm not quite at the 3% level of completely unable to form mental images, but I'm close. In particular there are three times I have vivid, sharp mental imagery, and the existence of such times tells me I have the brain hardware to visualize. It's enough to let me know that I want it all the time. Unfortunately I don't know how to get it. And searching online has proven difficult and frustrating... for example this article is first of all about a different meaning of "visualize", it's talking about some kind of self-help motivational thingy, and second of all it starts by saying "How to Visualize: I want you to relax and close your eyes. Picture a hot, sunny day at the beach."
Full Stop. Halt, Catch Fire and Burn.
That's already too far. For those of us who don't visualize, practice definitely does not consist of pulling up mental images, playing with them in new ways, and expanding our imagination. I'm very good at imagination in some ways, but I lack that first ability to pull up a mental image. That's what I want to learn how to have!
Here is a description of what I can do, what I have tried, what I have learned, etc.
I see vivid visual mental imagery in 3 situations: