I think the book has some genuinely good points, e.g., the benefits of positive thinking, developing goals, regularly reviewing them, and lots of illustrative anecdotes. But I think one's success is ultimately much more than the product of one's own thinking.

How about this more biblical emphasis? "Do not be conformed to this world, but be transformed by the renewal of your mind, that by testing you may discern what is the will of God, what is good and acceptable and perfect" (Rom 12:2).