Yeah, self-discipline can be a tough one.. I have also had that problem mainly in the past. One of the main things I have started doing differently, is thinking about things less. We spend so much valuable time, on worthless things, such as pondering. If that time is rather used to take actions, you will get addicted by the results you reap. That addiction will replace the need to be disciplined. It'll become second-nature.
Hope this helps :)