Many times people have had a conversation with an NLP coach about their inability to make pictures in their head. Often it's the process of not realising that they actually do it already, and sometimes it's a process of not following instructions.
Whatever it is, as a coach you need to have behavioural flexibility and respect the client's model of the world. After that it might be a good idea to work out how the client "does it".
Here is an example; I was having a phone conversation with a client who claimed that he could not make pictures in his head. I asked what he did for a job and he told me that he'd retired. I then asked 'what have you retired from?'. He said "I was a construction engineer".
Now immediately I knew that you would have to be able to visualise or make pictures in your head in order to see a construction project completed or even to see it get started. You would need to look at the risk assessment, create an idea in your head of how to overcome those risks, and each part of the project would need to be visualised before being put into a plan.
At that point he started talking about the building's location, the height, what it was made of, and I could hear him thinking, I really could. Then he started talking about a project just like that he was working on.
At that point I stopped him and asked him if he could see that project in his mind now? 'Of course' he said. 'We worked on it for about a year". My response to that was "so you can see pictures and visualise!'.
He laughed and said well I guess I do!
So when it comes to the use of visualisation, I would suggest that having a picture of yourself successfully completing an event would be more compelling then just talking through it. If in the future you come across this, ask the person to describe something to you, like their kitchen. In order to do this, they would have to have an image of the kitchen in order to tell you about it. Then tell them to imagine standing at the stove top looking at the pots (associated). Then tell them to imagine seeing themself standing at the stove top looking at the pots (disassociated).
It's that easy. Sometimes people like to make the process harder than it needs to be. Over the years I have had many people tell me they cannot make pictures, yet after 5 minutes I have them describing things in detail and I can see by their eye patterns that they are making pictures in their mind.
Visualisation, creative imagination, or pretending, are all much the same. Remember that the effects of seeing yourself in the future completing something successfully can make a massive difference to the outcome.