Discipline is your friend. It keeps you doing things that are good for you, like going to the gym or saving a portion of each paycheck. It gives you a framework for living so you won’t panic if something goes awry. It gives you direction so you will stay on track in all your endeavors.
The armed forces instill discipline to be sure each new recruit will work with the team and be effective even in life and death situations.
You can become more disciplined simply by practicing. Today you can skip the doughnut and have a salad instead. Today you can put an extra $5 in your savings account. Today you can take the stairs rather than the elevator, Practice, practice, practice. Then it becomes natural, a part of who you are.