People who already have a high degree of self-discipline as children are fundamentally more successful and happier in life. For all will-less procrastinators, smokers and couch potatoes this is seemingly bad news. But the good thing is: you can train your willpower!
Willpower: Rediscovering the Greatest Human Strength
Positive thinking makes life easier, but the key to success is discipline. Fortunately, one can practice discipline by training one's willpower.