You will fail, or have already failed, in controlling your time only if you do not have self discipline. Or if you lack self-determination. They actually come together. What you need is a real confrontation with yourself are you decided to really make your studying effective? How much are you willing to sacrifice for it? Where are you weak and why? You, must exert real efforts to control time. Unless you do, you can never aspire to study and learn effectively, much less get to the top.
Your self-determination and self disciplines can only be as strong as your desire or motivation. Try your best to work on your mind. Recognize the destructive force of procrastination and refuse to give in to it. Be your own master. Real victors are conquerors of themselves.