The mind is a wonderful gift that the Lord has given to us, we need to learn to control our minds and discipline them to focus on that which is true, noble, just, pure, lovely, and of good report. That is where true contentment, and satisfaction comes from. Yet this can only be done, as we develop our relationship with the Lord Jesus Christ. It starts at salvation, but it must continue to grow and develop. Knowing what God has done for us, and continues to do for us, is a key to learning to meditate on the things outlined in Philippians 4:8. Stay in the Word of God and allow that truth to transform your thinking.