The Lord has made clear the way to a healthy soul.
Remove your attention from yourself, and look unto Jesus - in the morning, later when thing get tough, and after the day when you are thoroughly tired.
Look to Jesus when you are tempted to resent the past or wonder about the future.
Refuse to decide why people do things or what they are thinking. Instead, look to Jesus. He does not have opinions.
Learn to identify your thoughts and line them up with His.