Control your mind - Surrender
The ability to control your mind begins with surrender. Jesus said, "Whoever finds his life will lose it, and whoever loses his life for my sake will find it." Mt. 10:39 (ESV). The "for my sake" part means selflessness. It means purpose, right-ness (righteousness), goodness, and new life.
The person who surrenders control of their mind to God's way will find control. Those who seek control within their self will lose control. This statement works because God's way works. Jesus is not so much making a promise granted only to those who follow him, worship him, or agree with his teaching. He is speaking truth. His is explaining how life works in his kingdom.