My psychic medium husband it trying to help me to learn to visualise.
All my life I have not been able to see anything when I close my eyes. All I see is darkness and I find it very difficult to meditate not being able to concentrate on images to help me. Does anyone have any suggestions?

As all senses are used in attunement, I would suggest you find a sound or taste or smell that works for your personal attunement process.  Visual is the strongest to be sure.  

How about picking a place you have actually been/seen?  Say a cottage or quiet place in a part?  Now you have something to see - not your imagination.

Does caffeine even in small amounts affect you ability of personal atonement to visualise?

Caffeine is a stimulant and all stimulants affect our abilities to be quiet and to use the sensitivities we all have.  They can be affected.

Do you sit in peace and quiet with your husband to meditate or do you do this on your own, or through a circle?

The easiest is prob through a circle as you will be taken on guided journeys with full protection of spirit and the circle leader. But be warned it can take years before you see or hear anything. Not everyone is meant to develop or can develop.

Use self hynpotherapy tapes and use breathing techniques, count backwards slowly from 10 to 1. Slow your breathing right down, cos thats the way to enter an altered state......

Practise, practise and more pratice, bit like driving a car and how determined are you and much does it mean to you to connect and work with spirit....

Like everything else your mind is like your heart, a muscle that needs training luv