The secret to motivation is not magic, it is not a secret and not a miracle either. Do not waste your best years on looking for something which is going to change your life instantly! Life is not about overnight success for most people; it is about daily little struggles which eventually add up to something greater than yourself.
What does this mean in real life? This means that you have to decide what your aim will be; so that you know how you like to spend your energy and efforts. You also have to decide whether you are going to be successful or waste your time on movies, games and other useless activities which do not contribute to those goals.
How to stay motivated
How do you stay motivated while at all these? You repeat the above every day to yourself and you remind yourself who you are and what you want. It will be difficult, because watching TV and playing games is way more fun than working your ass off. Yet, the rewards you get from working your ass of, are worth a fortune and the rest is just trash.