And the prospect of trying to find some acetate to put over the computer screen equally wasn't really going to work. I needed a better system... and found it at www.shutterfreaks.com/actions/freeelements6actions.html. They have quite a few things on there which might or might not appeal, and which might or might not match whatever editing software you're using. Worth a look, anyway. Basically, you load it up (even delving into hidden files on my computer which again is a leap into the unknown) as part of Elements, open an image and apply either the golden mean or the rule of thirds, and a grid appears... as in the screenshots below. You might have to click on the pictures to be able to see this properly, unless you're working on a huge screen. There is a version of the plug-in which shows you which bits you should crop to make it fit the golden ratio - maybe something for later.
Anyway, the windmill pic... looks as if I could have done with a few more daisies at the bottom to get the proportion of this right, and I'd thought that at the time, in fact - unfortunately there weren't any more!
I'm pleased in this image to see the line of buildings is precisely along that middle section, and the detail of the railing almost entirely within "the larger section" of the image.
Not so sure about this one, there's not enough to distinguish the larger and smaller parts and probably some more sky would have enabled the image to "breathe" a little more and fitted nicely into a "larger part".
This hellebore is reasonably satisfying from a golden mean point of view, with the in-focus flower head more or less remaining within the "larger part" and the out-of-focus elements remaining around the edges.
This hilltop view also works well in that the trees on the top comprise the "smaller part" and the grass in the front the larger. There is also a golden spiral, I think, and I wonder whether the pathway would correspond to those rules.
Overall, I'm pleased to see that the images that I was instinctively pleased with in terms of the composition e.g. the hill and the seaside scene seem to some extent at least to conform to the golden section, which identifies as a useful tool to use.