This week, a young man transitioning into the Reformed world wrote to ask for advice on systematic study. Here is part of my response:
Similar to your experience, Reformed theology has been revolutionary to my beliefs and outlook. The spiritual depths our tradition invites us to plumb are unfathomable! My take-away, however, is that grasping and routinely applying the basics of the faith—the doctrines of grace, the Lord's prayer, ten commandments, and Apostles creed—is far more important to practical godliness and service than is knowing all the esoteric arguments, or staying abreast of the ceaseless debates, which preoccupy many graceless souls.
Do not understand this as a discouragement of systematic study, which has its honorable place, but remember to "keep the main thing, the main thing." No believer has time for detailed theological studies, who does not first make time to pray, read the Word, and show meaningful love to others. There is no genuine advancement in Christian knowledge except that which tends to increase your intimacy and obedience to Christ, and stimulate compassion toward your neighbors.