Here is a very simple challenge. A lifelong discipline of scripture memory is an easy and effective way to a thorough knowledge of the New Testament. If a believer memorizes two verses a day, he or she can memorize the entire New Testament every ten years. If instead of memorizing every verse and only memorize key passages, in three or four years, a total mastery of the New Testament can be obtained.
Another benefit is that scripture memory gives a way to bracket the day with one thought with morning and evening meditation. Another benefit is that a single topic can be contemplated for about a week or so as most paragraphs are 8-12 verses long. Over the course of say 3-4 months, your meditation has been centered on one book of the bible, and, though this is a slower method to proceed through the New Testament, it is far more effective in learning the thoughts of the author.
Also, this is something, we can do with a friend or a spouse. This practice is my commitment this year, and, hopefully, by God's grace and the encouragement of friends, a commitment I could keep for the rest of the decade or even the rest of my life.