So, you procrastinate. A lot. And it's a really big problem in your life, and so you really want to, y'know, stop procrastinating. But for some reason, it's just not that easy.
So, why do you procrastinate?
It's probably a really hard question to answer. Is it "because I'm lazy"? That's not a useful answer, because "stop being lazy" is just as hard to do as "stop procrastinating". How about "because of akrasia"? That's not a real answer; that's just a restatement of the question in more vague terms. Maybe "because of hyperbolic discounting"? Even if that's true, that's not really a useful answer, because there's no way to turn hyperbolic discounting off. (Or is there? If you know of a way to turn hyperbolic discounting off, please tell us.)
Maybe your procrastination has three parts. First, once you start doing something interesting, it's very hard for you to stop; second, having stopped, you don't usually feel like starting to do something useful; and third, having started, you often find yourself losing focus and wanting to do something else.
So let's look at each of these parts in turn.
Once you start doing something interesting, it's hard for you to stop.
For you, this one's a pain in the ass. (I know this because for me, it's a pain in the ass, and since you're reading this article, you must be identical to me.) You've told yourself that once you find yourself doing something interesting, you're just going to stop immediately. But that doesn't work at all. You've tried setting a timer, and telling yourself that you'll definitely, absolutely stop when the timer goes off. But that doesn't work, either; you just ignore the timer. What if you set a timer to repeatedly and annoyingly beep at you until you tell it that you've started working? You repeatedly ignore the timer and quickly become annoyed.
For you, once this problem has started, there just doesn't seem to be a way to stop it. So the solution is to just not start in the first place. The ideal situation is that you're not doing any interesting and fun activities whatsoever until you're done working for the day (unless, of course, one of those activities is part of the work you're supposed to get done).
You should still take breaks, of course; don't expect to work for four hours solid without stopping. Just don't do anything interesting during your breaks. Listen to music, or stare out the window or something.
And, of course, this raises the question: how do I avoid doing these interesting activities? It turns out that, compared to the rest of your procrastination, this one is really easy to deal with. Hopping on Facebook or whatever when you're not sure what to do is a breakable habit. So break it. And how do you do that?
One technique is to neuter the worst culprits. Go into your computer's configuration and tell it that reddit doesn't exist. Then if you accidentally try to access reddit, you'll just get an error message. Stop making status updates on Facebook, don't accept friend requests, and block everyone from showing up in your news feed. Disable your IRC bouncer and only access IRC through the server's crappy web interface. Avoiding temptation is easier when you set yourself to be disappointed every time.
Still, there's a bit of residual temptation left over. How do you avoid this? Just use plain force of will. Tell yourself, "I need to avoid doing this right now." That ought to work. Hopefully.
So now that you've got that fixed (kind of), you've got another problem on your hands.
You're not currently doing anything addictive, but you just don't feel like working, either.
The easy answer to this question: just do it anyway. You may feel kinda crappy, but this doesn't actually have any negative effects.
Or maybe you really, really don't feel like working. All right. Why not? Is it because there's a fuckton of stuff you have to do, and getting it all done is going to suck royally? Well, you can only do one thing at a time, so figure out what the one thing you should do next is, and completely ignore every obligation except for that one. (Figuring out which task is the one you should do next should be easy. If it's not easy, make a to-do list and use it properly.) If that little piece still seems too arduous, figure out the next little piece of that little piece that you need to do, and ignore the rest of it for the time being. Repeat.
All right, so now you're working (hopefully). But it's not going very well.
You're working, but you're not focused on your work at all; you're just thinking about other unrelated stuff, and about how much you'd like to do something other than working.
Part of the problem here is that you have ADD. (Since you're reading this article, I'm assuming you're identical to me, and so you have every disorder I have.) Consider medication and talk to your psychiatrist. Therapy's probably a good idea, too, and it's easier to get seen by a psychologist or therapist than by a psychiatrist.
Remember to eliminate distractions, too. Close unnecessary browser tabs and applications. Set your IM status to "do not disturb". Maybe try writing some of your thoughts down.
And once you've done that... hell, I have no idea. Good luck.