Master your thoughts. Any thought goes on inside your mind. Watch for a few minutes and you will be surprised: the mind seems to be crazy! It jumps from one thought to another thought for no reason at all.
Be quiet, and loving and fearless. Three things Buddha says: Be quiet—learn to be silent more and more—and loving, because if your silence is not loving it will make you insensitive. Then your silence will be that of a cemetery—dull, dead.
Zazen means just sitting doing nothing. The first thing to do is learn sitting, a deep restfulness. Become a pool of rest, not even ripples of desire, going nowhere, no ambition—not even for God, not even for nirvana.