Brother Lawrence in The Practice of the Presence of God says "If we do what we can on our parts, we shall soon see that change wrought in us which we aspire after." Easier said than done. You have to live moment by moment--"in the now"--if you are to consciously choose anything other than your habitual response. It requires patience and self-control--both of which I find in short supply! But when I do change my thoughts, things change as well. "Be ye transformed by the renewing of your mind." (Romans 12:2) And conversely, I've found it to be true that we can be renewed by the transforming of our minds.