I must admit to that some people who take my class "have it" and others do not.
What am I talking about?
Vision. Not the kind you have by looking with your eyes, but the kind you have by being able to imagine things in your head. The shape of things. How they will look and fit together. How wood will look as far as color, figure and texture...
Working in a technical field, I look at lots of drawings and models and parts, so I guess I have a fairly highly developed sense of "vision". As a teacher, it's my job to explain the next steps in the boat-building process. (Usually with lots of pictures on a whiteboard.) I have to get my point across so that the students will be successful at what they are trying to create without having much to look at, really. Some people pick this up pretty quickly, and others probably never will.
I find this sad, really.
A good example of this is my DW. We were living in another house with a mostly functional, but tired and cosmetically awful kitchen. I had a picture in my head of what I wanted the kitchen to look like and drew projections looking at the two major walls of the kitchen showing the cabinets, appliances, windows, doors , switches and outlets. I also had a floor plan which showed the floor plan of the kitchen with these things in it. When I showed these drawings to my DW, I think she couldn't "picture" the kitchen well. Still, she let me go ahead. In hindsight, she really showed a lot of faith in letting me rip out the kitchen and bring it to reality!