Self discipline, like everything else, takes practice. I’ve have been working on mine for over 25 years. I am a lot better at it each year, but I still work on it constantly. It’s a journey, not necessarily something that you attain perfection of. I would start by making one small new change each month (to your diet, to the amount of exercise you get, to the amount of sleep you get, etc.) and build on it each month. Over time, you will see some progress. If you get to the end of a month and don’t feel comfortable adding another change, then don’t. Wait till your body and mind have adjusted to the last change you added and it is incorporated into your daily life. If you try to change everything all at once, you will overwhelm yourself. The small changes that you make and give yourself time to become accustomed to will last you a lifetime. Rushing changes will cause you despair and will not become routine. Twenty five years ago I exercised sporadically and ate crap. Over the years I would exercise more each year and make small adjustments to my diet. Now, 25 years later, I go to the gym 6 days a week and love it and I eat really healthy 95% of the time (I still need to eat chocolate and have a glass of wine on the weekends). It has become a part of who I am now and I don’t feel right about myself if I stray too much from these routines that I have forged over the years. That is what self discipline is all about. You don’t need a boot camp drill sergeant, become your own drill sergeant!