Stand the log section on a larger log or solid earth. Line up the splitting ax so that its blade meets the edge closest to you, with one-third of the blade hanging off—you don't want to bury the blade in the center. Grasp the end of the handle with one hand and the top of the handle with the other, and raise the ax overhead. Now swing, letting the handle slip through the top hand, and drive the blade into the perimeter.
Tip: "If wood is your primary heat source, it's worth investing in a log splitter. It's a real labor-saver."
—Roger Cook, TOH Landscape Contractor