In Romans 12:2, Paul urges Believers to be transformed by the "renewing of our mind." I will not overcome the hills ahead of me in life through physical training, but through spiritual renewal of my mind--what I trust to be true about God and His purposes.
I renew my mind by thinking, meditating on and engaging what is true and good. Philippians 4:8 states, "Finally, brothers, whatever is true, whatever is noble, whatever is right, whatever is pure, whatever is lovely, whatever is admirable—if anything is excellent or praiseworthy—think about such things." Paul's charge suggests that we don't form opinions, values and ideas simply as passive participants in culture. Rather, we can choose to invest ourselves in the kinds of literature, dialogues and influences which will cultivate godly thinking, wondering and creativity.
A few points of action:
1. Immerse yourselves in God's Word. The way of God is revealed in the Word of God.
2. Select your books with care. I fear that there are more mediocre books about the spiritual life published each year than truly valuable ones. Remember that "best sellers" are not always best.
3. Variety makes for a good diet. Explore theology, Christian fiction, devotionals, contemporary and ancient writers. Branch out.
4. Clear your coffee table. I have subscriptions to 4 magazines that taunt me every month. I don't have time for that many. Some people do. Manage the number of data channels [subscriptions, social networks, books, television, etc.] you take in. Remember, garbage in, garbage out.