There is an amazing book called The Slight Edge which is based on this very principal and it can really change your life. Here is a small excerpt from it that really resonated with me:
It sure would be nice if, somehow, you could do something dramatic. If you just wake up tomorrow and have it all turned around—snap your fingers and change it. That might happen, in a movie.
But this is your life. What can you do? What happens if you add one small, simple, positive action to the success side?
Nothing you can see. What happens if you add one more? Nothing you can see. What happens if you keep adding one more, and one more, and one more, and one more ... Before too long, you see the scales shift, ever so slightly. And then again. And eventually, that heavy - failure side starts to lift, and lift, and lift ... and the scales start swinging your way.
No matter how much negative weight from the past is on the other side, just by adding those little grams of success, one at a time (and by not adding more weight to the failure side), you will eventually and inevitably begin to shift the scales in your favor.
The Slight Edge is about your awareness. It is about you making the right choices, the choices that serve you and empower you, starting right now and continuing for the rest of your life, and learning to make them effortlessly.
It's not a question of your mood or your feelings. And it's not a question of will power. It's a question of simply knowing.
Simple things you do every day, in fact. Or, as the case may be, don't do every day. Time will be your friend or your enemy; it will promote you or expose you. It's entirely up to you. If you're doing the simple disciplines, time will promote you. If you're doing the few simple errors in judgment, time will expose you, no matter how well you appear to be doing right now.