A wire fence enclosure keeps leaves in place. This pile has shrunk considerably as the leaves have broken down.
Nothing could be easier than making leaf mold: All you really need is leaves and time. Since I have only a few deciduous trees in my yard, I import leaves into my garden each November. They arrive by the truckload in plastic bags from my neighbors and from a local landscaper. I create a 6-foot-diameter ring with 3- or 4-foot-tall wire fencing and just dump the leaves in, packing the pile down as I add to it. An enclosure isn't necessary, but I find that it helps to keep the leaves contained and more compacted. About two years after I build a pile, it has shrunk considerably, and the leaves have been transformed into a rich, brown, crumbly leaf mold.
Leaf mold is something gardeners can never have too much of. It is useful in container plantings, in the ground, and on the ground. When sieved through half-inch hardware cloth (steel mesh), it becomes an organic amendment for potting soils, helping to increase the mix's aeration and water retention. Substitute it for peat moss in potting mixes by combining it with equal parts of soil and perlite or, for a soilless mix, with an equal part of only perlite.
Out in the garden, mix abundant quantities of leaf mold into the top 6 to 12 inches of soil where you need to loosen up sticky clay. When laid on top of the ground, leaf mold is an attractive and functional mulch and a natural foil for flowering plants, especially in a formal flower bed. There's no need to dig the material in at the end of the season, either; just pile more on top.