How can I motivate myself to do the things I want to do in life?

It's like I have a blueprint of my life laid out in front of me that contains all the things I want to learn, the things I want to do, who I want to be... but yet wanting those things is just not enough to keep me motivated to actually do them. For example when I go to the bookstore I buy a bunch of books, but then I end up not reading them. And when I'm trying to learn a language, I learn the basics, but then I get bored and move onto another language. I do everything last minute for school, and I can never really focus. Although I get good grades, I still have a sense of unfulfillment because I feel like I just breezed through all of my cles without learning anything worthwhile. I don't see how I'll ever get anywhere in life with this problem. I just feel so lazy and useless. How can I find the motivation to buckle down and do things instead of just thinking about them?