I use paintings, usually with perpesctive (depth), for instance landscape, with buildings, people or animals, or objects.
Generally, I use picture files with a high resolution, in order to zoom in.
Then I imagine a path, most of the times clockwise, usually from farest to the nearest point in the right side of the painting, then in the down part, in the center, then to the farest point in the left side. I find this path easier than a grid-pattern.
With powerpoint I place the loci (with a different color for the loci 5, 10, 15, etc).
I first learn loci 5, 10, 15, 20, etc, in order to avoid loosing/forgetting a locus when I recall the path ; then I learn all the loci, and link them with the stuff I want to learn.
I hope my explainations were clear enough. This is one example :
