Self-discipline is the ability to focus and overcome distractions.  It is taking action in accordance with what you think instead of how you feel.  If you can overcome the urge to act and speak as a response to your feeling in the moment you can begin to control more of your future. Often our ‘heat of the moment’ responses cause us more stress and work, so developing self-discipline is one of the most important things you can do to improve your productivity, lower stress levels in your life, and improve your reputation.

But remember, self-discipline is just one tool available to you. It won’t magically end your stress and procrastination issues overnight.  Self-discipline CAN help you overcome barriers you reach in your journey to more productive, less stressful, lives.

Self-Knowledge

You need to know what action best reflects your goals and values. Write down your goals, dreams and ambitions. Write a personal mission statement to help you have a greater understanding of who you are and what you value.
FranklinCovey has a nice mission statement builder.  It will guide you through steps where you answer questions, not simple questions, but if you think about each answer carefully and provide honest answers, at the end you will have a very nicely written, direct and to the point, life mission statement. (You do need to provide your name and email address to use the tool)

Awareness of Your Current Behavior. Acceptance

If you aren’t aware your behavior is undisciplined, how will you know to act otherwise? Developing self-discipline takes time, and   you have to be aware of your current behavior to catch it, and change it.

Acceptance means that you perceive reality accurately and consciously acknowledge what you perceive. Without acceptance you get either ignorance or denial. With ignorance you simply don’t know how disciplined you are — you’ve probably never even thought about it. You don’t know that you don’t know. You’ll only have a fuzzy notion of what you can and can’t do. You’ll experience some easy successes and some dismal failures, but you’re more likely to blame the task or blame yourself instead of simply acknowledging that the “weight” was too heavy for you and that you need to become stronger. When you’re in a state of denial about your level of discipline, you’re locked into a false view of reality. You’re either overly pessimistic or optimistic about your capabilities.

Commitment to Self-Discipline

It is not enough to write down your goals and values, you must make a commitment to them. You may feel you have no self-discipline now, but you do, even if a little, and you use that to make your self-discipline skills stronger, and each time you commit to working on increasing your self-discipline, your skills get stronger and stronger. It takes willpower, hard work, and industry. Industry is working hard. In contrast to hard work, being industrious doesn’t necessarily mean doing work that’s challenging or difficult. It simply means putting in the time. You can be industrious doing easy work or hard work.

Disciplining yourself to be industrious allows you to squeeze more value out of your time. Time is a constant, but your personal productivity is not. Some people will use the hours of their day far more efficiently than others. … Give an industrious programmer a 10-year old computer, and s/he’ll get much more done with it over the course of a year than a lazy programmer with state of the art technology.

Selected portions from 12 Universal Skills You Need to Succeed at Anything.