Will triumphs most. Willpower is the basis to improvement. You have to want to genuinely want it and not just because you think you should. That applies to most things, but in a practical sense, you need to have a strong willpower. To the surprise of most, you can improve your willpower everyday. It could be the simplest thing, you could refuse something unhealthy that you would have otherwise wanted to consume or run an extra 5 minutes after you're about to give up on the treadmill. The simplest steps, the things you do everyday are what end up making up the majority of your time and really your life. If we really take control of the simplest, easy to control aspects of our lives, we empower ourselves to command the rest of our lives off that momentum!