It's not motivation you need, that comes in waves and bursts. What you need to learn is self-disclipline. It's something I've struggled with all my life. I'd get these random burst of motivation and work my ass off for a week straight, then once that motivation disappeared, i'd stop what I was doing and move onto the next thing.
I still struggle with it, but im working hard on improving it and I have gotten better. Working when you're motivated is easy, what will make you successful is working when you have no motivation and sticking to your plan. Self-discipline is like a muscle, you need to train it and it'll continue to get easier. I find that just starting is the hardest bit, once you actually get into the work you'll find its not that bad.