One of the keys to success is passion. If you care about something or want it naturally you won't need to force yourself to work on it. The passion will be your fuel. Only work on things you are passionate about.
i still find each day too short for all the thoughts I want to think, all the walks I want to take, all the books I want to read, and all the friends I want to see. - John Burroughs (I'll add, and all the sleep I want to sleep :)