I'm a big procrastinator, but I finally found a way to get around it. Instead of thinking about the big tasks, I just allot myself a fixed amount of time that I'll be doing something, work on it steadily during that time, and quit at the end regardless of the state it's in. For some reason, it really makes it easier to face big important projects if I just say "I'm going to spend 8 hours putting up siding today, then I'm done" as opposed to "I need to get that siding put up..." I've used that trick to get tons of stuff done around my house as well as to write a book (which hasn't been published yet because I've been putting it off, so I guess there's still room for improvement).
This is a bit like Raymond Chandler's process for writing:
> The important thing is that there should be a space of time, say four hours a day at least when a professional writer doesn’t do anything else but write. He doesn’t have to write, and if he doesn’t feel like it, he shouldn’t try. He can look out of the window, or stand on his head, or writhe on the floor. But he is not to do any other positive thing, not read, write letters, glance at magazines, or write checks. Write or nothing.
He commented somewhere that it works on the same principle as school - you can't force children to learn, but if you prevent them from doing anything else, the bright ones will learn just to stave off boredom.
1. Force yourself to sit here and do nothing else until the task is done. The Chandler method, which requires a great deal of discipline.
2. Keep telling yourself "I'll start just after I check Hacker News / Twitter / watch one more episode on Casualty". This means you never achieve anything and feel forever guilty and worthless.
3. Put the task to one side for now and do something else enjoyable and marginally useful. You make progress in other tasks, feel valuable, and only a little guilty.
Structured Procrastination is the third option. If you can't manage Option 1 -- and who can? -- it's better than Option 2.
The trick for me is always just getting started. Once I actually get over the hump and start working, I generally find it's pretty easy to keep going. It's getting started without sidetracking myself that really puts up the biggest resistance.
That may not work for an author who's lacking inspiration, but in my case I found that when I sat down at the keyboard to work on my book, if I couldn't think of what to write I'd just start writing utter crap for a while until it started to flow a little better, then I was usually off to the races.
Note that Chandler's approach very specifically did not involve getting a task done. He was talking about writing novels over the course of months or years, not little things he was putting off.
Also it's a task where inspiration is involved, so if he forced himself to write every day no matter what, some of it would be worthless because the ideas weren't there. The point of his approach is to make habits that ensure you accomplish something in the long run, regardless of whether you get something done today or not.
I think what you're describing is something similar to pomodoro technique (http://pomodorotechnique.com/), only on bigger scale (8 hours at once). Maybe you will find it useful.
I tried pomodoro but never sat well with me. I can focus for 1-2 hours happily once I'm into something. I worked in a team where it was pushed as a mantra for working. The issue with that being is that everyone was on a different schedule. I actually considered it a way to attempt to kill social interaction within the team, say going for coffee together.
If it works for you, go for it, but I do not work in 25 minute chunks.
1. Boxing sufficiently large chunks of time that I can actually work on a project. Task-switching has immense costs.
2. Actually having a path forward. If I've yet to find a good way to tackle a problem, or worse, if I'm stymied by having been mislead as to a possible pathway (a false Bayesian prior, or similar concepts in logic/truth), it can be quite frustrating.
