When I go to sleep, I am thinking words in my head that eventually become nonsense thoughts that I am not in control of and then I fall asleep. When my girlfriend goes to sleep, she sees a kind of black and white spherical planar blob thing until she falls asleep.

I tried falling asleep to visual imagery a few nights ago and it worked. I saw nothing for almost exactly 15 minutes, but then some natural reaction must have happened as I started seeing a surprisingly vivid black and white spherical image blob thing.

So in training myself to think more visually, that's about as far as I've gotten.