In walking meditation, the primary object of attention is the process of walking itself. In other words, to sharpen awareness and train the mind to concentrate, you pay close attention to the physical act of walking, the way you take one step after another.
Practicing walking meditation encourages the development of mindfulness in ordinary daily life. If you can learn to establish awareness during walking meditation—that is, while you are physically moving with your eyes open—then it won't be difficult to arouse that same wakeful quality during other activities, such as eating, washing dishes, driving, or, of course, practicing yoga. Your meditation will begin to permeate your entire life.
If, while walking, you become aware that your mind has wandered away, clearly note the distraction and gently but firmly bring your attention back to your steps. Experiencing the simplicity and peace of being with one step at a time—with nothing else to do and nowhere to go—can be liberating.