“One of the most powerful spiritual practices is to meditate deeply on the mortality of physical forms, including your own. The physical form dissolves and is no more. Then all thoughts also die. Yet you are still there—the divine presence that your are. Radiant, fully awake.” Ekchart Tolle (from A New Earth)
Since we live now entirely is a world created by thought (names and forms are thought), meditating on the mortality of physical form is meditating on thoughts. And how does one do that? You don’t meditate on a form by focusing attention on it. You meditate on something by releasing your focused attention, but at the same time you don’t leave the scene. This is relaxed attention. By opening the fist of thought, you allow thoughts to blow away. The thoughts of form only exist when you grip them with your attention.