It's truly the worst thing that you can do for yourself. Procrastination will prevent you from advancing in your career, schooling, with relationships, everything. It's a vicious cycle that needs to be broken in order for you to live the life you want, and it's not as hard as you might think.
Granted, if you put off reading this article, you're just letting the problem get worse. I'm assuming that you're going to read on, though, because you want to break free from it.
Flat out, procrastination is a conditioned habit. The more you do it, the more you learn that it's okay, and the more you'll keep doing it. The first step to fixing it is to know that you need to do something about it.
The second step is to realize that it's all within yourself. Nobody other than yourself causes you to put things off. Many people say that they weren't feeling well, or that they were stressed, and that's why they put something off. While they peg that as outside influence, it's themselves that they have to blame. You don't want to be like them, so you're going to realize that you personally are wholly responsible for procrastination.
Now that you've realized that, you need to make steps toward breaking the habit. Next time you feel like putting something off, work that much harder to keep at it. Over time, it becomes easier to deal with as you learn that what you were doing was not actually that terribly difficult, just that you were building up to it tremendously by procrastinating for so long.