Finally, brethren, whatever is true, whatever is honorable, whatever is right, whatever is pure, whatever is lovely, whatever is of good repute, if there is any excellence and if anything worthy of praise, dwell on these things. (Philippians 4:8)
Years before I was a Christian and knew very little about God's word, the Bible, I read a lot of motivational books, including a popular book by Dr. Norman Vincent Peale, "The Power of Positive Thinking". Translated into fifteen languages and with more than 7 million copies sold around the world, this popular book was suppose to: restore the faltering faith of millions of people in themselves offering his profound method of achieving happiness and success by re-channeling thoughts and energies into a powerful, positive current -- one that will raise you to heights you never dreamed possible!
Don't waste you time reading Dr. Peale's book. It may contain a few nuggets of truth, but it is filled with heresy and false hope centered in frail human potential. Instead, read the Bible and dwell on God's almighty power; All Scripture is inspired by God and profitable for teaching, for reproof, for correction, for training in righteousness; so that the man of God may be adequate, equipped for every good work.(2 Timothy 3:16)
There is indeed power in positive thinking-- positive biblical thinking! If we are to be happy, successful, productive Christians, we must continually read and meditate upon the eternal truths found exclusively in God's word; Let the word of Christ richly dwell within you... (Colossians 3:16)
By the way, the Bible is the worlds best-selling and most widely distributed book with more than 5 billion copies in print translated into more than 2,800 languages! Maranatha!