"For My people are foolish, 
They know Me not; 
They are stupid children 
And have no understanding. 
They are shrewd to do evil, 
But to do good they do not know."
‭‭Jeremiah‬ ‭4:22‬ ‭NASB‬‬
The Lord's criticism of Israel in this verse made me ask myself, What am I shrewd to do? Am I learning more and more how to do good, or how to do evil? I believe it is our calling as Christians to be the exact opposite of the example above. Paul says to the church in Rome, “... I want you to be wise in what is good and innocent in what is evil.” (Romans‬ ‭16:19 ‭NASB)‬‬
How do we become wise? The Bible tells us to practice:
“But solid food is for the mature, who because of practice have their senses trained to discern good and evil.”
Hebrews‬ ‭5:14‬ ‭NASB‬‬
This word "practice" is a very interesting way to describe those who are mature in the faith. Clearly, the Israelites had made a practice of doing evil to the point that they were "shrewd to do evil," but ignorant of doing good. Since we are called to a different standard, and want to grow in maturity in Christ, we must make a practice of doing good. 
What does it mean to practice? To practice is to make a regular, concerted effort at behaving in a certain way. Our daily behavior is our our practical practice, and through simple daily living, we are practicing in a direction we will ultimately go, whether to good or to evil. 
Said differently, I become good at what I practice doing. 
I don't know anybody who wouldn't like to be known as a "man or woman of prayer." It's like saying you don't want to be Lionel Messi, the greatest soccer player in the world. Everybody wants to be Messi, too. But what makes Messi, Messi, is practice. He BECAME Messi. Do I want to be a man of prayer? That also starts with practice. 
It'd be absurd to say, "but I'm not good at soccer yet. I'll do these other things I enjoy until I get good, and then I'll devote myself to it." But the ability flows from devotion, not the other way around. Devote yourself to practicing something, and some measure of ability -- certainly more than you presently possess -- will surely follow. And the same is true of prayer, or any other spiritual pursuit. It would be equally absurd to say to ourselves, "I will do that after I get good at it; for now, I'll just do other stuff."
We hear a lot about "freak athletes" but rarely do we associate that with "freakish devotion;" we think of a "freak athlete" as meaning "naturally endowed" rather than "passionately obsessed with improvement."
I heard an interview with some NBA players who played wth Kobe Bryant. At the time he was considered the best basketball player ever outside of Michael Jordan. These players talked about how they would arrive in a new town for a game, and the first thing all the players did was find the best restaurant to eat and party. But anybody knew if you needed to find Kobe, he wouldn't be at the restaurant; you had to go to the gym, because that's the first place he went wherever they landed in a new town, "to get his rhythm back." To the uninitiated, it seems absurd that, of all players, the very best one is the one who needs practice; yet those who understand will say he is the best for the very reason that he is always practicing. He chooses to practice more over many other things, even when others are satisfied with their level of attainment. This is what it means to be "passionately obsessed with improvement."
This makes me think of Jesus asking His parents, "didn't you know I had to be in my Father's house?" in Luke 2:49. He had obviously made a practice of spending time listening to God's Word being read in the synagogue. Just like Kobe Bryant seeking out a gym in any new town, Jesus sought out the synagogue to get practice in the things of God. 
Jesus said "I had to be in My Father's house." Where do we feel we "have to be?" If the people you know need to find you, where would you tell them they "have to" look? (I'm speaking metaphorically -- it need not be a physical place at all) The answer to this question, I believe, reveals what we are passionately obsessed with improving. 
The thing we have to examine is our free time. 
“'How can you say, 'I am not defiled, 
I have not gone after the Baals'? 
Look at your way in the valley! 
Know what you have done!...”
‭‭Jeremiah‬ ‭2:23‬ ‭NASB‬‬
When the people plead innocence, God tells them to "look at their way in the valley," to see what their true condition is. Meaning, consider your behavior in the times of peace and ease. What do I do with my rest?
How do I conduct myself when released from my obligations and worldly responsibilities? For example, with my down time, am I becoming a man of prayer? Or am I becoming a man of entertainment? I can know by looking at what I do: if I seek to pray during my down time, I will become a man of prayer; if I routinely seek entertainment, I will eventually become a man of entertainment. 
However I conduct myself on a daily basis is what I will eventually become, whether by default or by intention. Many default through unintentionality to mediocre pursuits that they would have never deliberately chosen. But those whose lives we admire, both in the world and in regards to our faith, are those who set their intention to mold their daily behaviors to achieve their end goal. Henry Wadsworth Longfellow said it well when he said, "The heights by great men reached and kept were not attained by sudden flight, but they, while their companions slept, were toiling upward in the night." 
I want to make a daily, deliberate practice of what I am passionately obsessed with improving: my devotion to and relationship with my Lord and Savior, Jesus Christ.