Who in their 40's with two adult children both in college, walks away from a fully furnished home to live on a college campus to pursue a college degree? Not a graduate degree, not as a graduate student but in pursuit of a bachelors degree? "I Did" Not that was self-discipline. 

If you want to become the master of your craft, an expert in your area search out and pursue everything you can about your area of interest. That means obtaining knowledge, which requires self-discipline. After you see it! After you say it! After you write it! Commit to it! Being committed is developing self-discipline.