I have only found one way of improving my visualization skills, and that is by practice. Everything else is temporary. For instance: On your next WBTB, get up a little longer and spend some time visualizing. It should be much more vivid and clear than any other time. This is when I see "how far I can go with my visuals" that is to try things like playing chess or pulling up random text and other things. If an entire scene comes, I am usually dreaming, and I start moving my body with the "imagination movement until I can feel it. Then I start moving like normal. If I move before I "feel" anything, I usually move my waking body.

It is ok, but it works about as well as any visualization exercise I have found. I make my own now.