I posted a reply yesterday, but it's gone now.

Anyways it had to do with using other senses like wow_nonamesleft mentioned. Instead of seeing things, feel them, smell them, hear them, heck... try licking stuff. The visual may appear on its own, and if it doesn't, no big deal. The point is to immerse yourself in it.
Since your a musician, your sense of hearing may be the place. Imagine yourself plucking a string on your guitar, really feel the strings on your fingers, and "hear" the individual notes.
Some people are better at visualizing than others - it's a skill.