I believe it all has to start with self reflection, and really taking the time and energy to sort through all the ads and media and other voices in your head to ask yourself what it is YOU want. And that doesn't always get figured out in one sitting. Once you do eventually start finding the answer is when you can start moving toward it.
This is where the self love comes in. If you know what you want, and you love yourself enough to give yourself that which will make you happy/ content/ fulfilled/etc., then you will find the discipline to make sure you get there. I think Will Smith was right in saying that "discipline" has taken on a very negative connotation, but it does not always have to be negative.
The video is pretty straight forward, and I believe the idea and the message is as well. If you have any thoughts, please feel free to discuss.
My overall takeaway: "Self Discipline= Do I love myself enough to do what it takes to get what I really want?"