First, you need to be clearly focused on where you are going, on what you want to accomplish. Determine not only what you want to accomplish, but also why. When you understand why you want success, you'll find a way to get it. You'll do whatever it takes. The why is critical.
Actions are vital, as well.
It's not enough to be positive and to be focused. These are important, but it is action that gets you where you want to go. In fact, it is action with which you convince yourself of your sincerety and desire. In the end, only you really know if you're sincerely working in the direction of your goals. Only you know if you're doing your best.