Love itself is the prime spiritual discipline. All others, including Bible study and prayer, are good only insofar as they serve to empower, amplify, or inform love.
Pianists don’t cultivate their skill and musicianship by reading books on the history of piano music or by talking with composers, as enriching and obliquely helpful as that might be. They improve by playing piano.
Similarly, the way you get better and more consistent at loving is by trying to love.