Also, here are two great resources for mental imagery and improving it that I have used/read-http://www.lucidcrossroads.net/howtodoit.htm
This is also a lucid dream guide of sorts but there is a section on "hooking" into the image, by making it have depth, and full field of vision/view that I mentioned and its a good read to understand what I'm talking about.http://psychclassics.yorku.ca/Galton/imagery.htm
>Statistics of Mental Imagery>Francis Galton (1880)
A very informative and eye opening study of the mental imagery vividness, clarity, and ability of a large sample size of adults and school children conducted in the 1800's. It's nice to know that even as far as then there were people interested in mental imagery and the way it varies from person to person.
The participants were tested on three major categories of their mental imagery faculties - Vividness, Color, and Mental field of view. The last bit, the mental field of view I think is what I was talking about and it shows that many vary on this category. One thing I noticed after reading the study is that my representation of color and stability in mental imagery is low, color is muted or not so vivid and stability varies from time to time, sometimes it may take great effort to keep an image solid inside my head and even then it will lose form or not appear all in one place but separated, like the example of the dinner table with many artifacts placed on it.
So it's good to know, reading that study that there are people who possessed incredibly detailed mental imagery, then the ones who had it about average and those few who had very low and almost nonexistent mental imagery faculties, the human brain has not changed much since the 1880's so suffice to say the same range of ability can be found today, I think it is possible to increase your capability and vividness of mental imagery though, especially after/during meditation as I have found out myself - the imagery was also much more colorful at that time too, I can recall it now even seeing glimpses of it in my minds eye but not to the great extent I did then.
Of note is that working on having better mental pictures, and working in tandem on mental auditory and olfactory and tactile sensations should significantly help with your lucid dreaming attempts especially in the formation of dream scenes during a WILD attempt but that is also something I need to work more on. However the most important primary skill to improve on should be visualization because it can greatly aid you or entertain you when you are not trying to dream and the easier it is to conjure up detailed and vivid mental images the easier it will be to do is during a WILD attempt and the rest of the sense will just kick in when a successful lucid dream unfolds around you.
Sorry for the wall of text but this is a topic I have great passion in. I once planned to meditate for an entire week or more and see if my visualization abilities improve but never dedicate the time to it, at least now after just one session that I mentioned I realize that it is entirely possible, and who knows how much more your mental imagery stability, vividness, field of view, color representation etc might improve after active effort, I really should give it another go.