The practice of meditation and the technique was devised by the Buddha himself. We know that he went through the same experiential process. Therefore, we can follow his example. The basic technique is identification with one's breath or, when doing walking meditation, identification with one's walking. There is a traditional story that Buddha told an accomplished musician that he should relate to controlling his mind by keeping it not too tight and not too loose (just as he would tune his instrument). He should keep his mind at the right level of attention. As we practice these techniques, we should put 25 percent of our attention on the breathing or the walking. The rest of our mental activities should be let loose, left open.
From "Continuing Your Confusion," in The Path is the Goal: A Basic Handbook of Buddhist Meditation, pages 18 to 19.