FP,
For the tangerine technique, put your hand on the top back part of your head. Let your mind feel your hand there. This means that if you can feel your hand there, your awareness is there.
The whole purpose of the tangerine is to widen your gaze in a relaxed manner. Look in front of you at one thing. Now just relax your gaze. Put your hand on the top back part of your head at the same time. Now see how many more things you can see w/ this widened gaze.
It's like when they say: Hey, back away from this xxxx, you're too close to understand it correctly. Same w/ your eyes. Feel your gaze coming from the top back part of your head and let that gaze be wide.
I'm like you in that i can't visualize really either. Don't let it bother you. As astrowill mentioned, there are the other senses. I'm good w/ kinesthetic stuff. I can really feel the way a rock rests on the earth. I use this image for relazing. Trying to visualize some nice scene is tough for me. But a huge boulder---i'm immediately relaxed.
enjoy your journey w/ PhRing 
