I second using the Pomodoro technique - without it, writing my book would've taken 3+ years instead of one.

The key is to change the structure of your environment to support the Pomodoro as much as possible. Turn off everything not directly related to what you're doing - phone, internet, etc.

I used Freedom (http://macfreedom.com/) to completely disable my internet access for 6 hours at a time when I scheduled a day to write. If I didn't disable the internet, I'd waste hours doing "research" when the going got tough. Without any net access, I was able to persist through the hard parts and write a huge amount in a day.

The pomodoro technique seems like allowing yourself a hit of heroin every few days, even though you know it's a problem. I've never been able to follow it for long enough for it to be effective. Any tips?

I guess you should try to see every time you fail to do a Pomodoro what it was that caused you to lose focus, and seek to eliminate that distraction.

For me, losing flow due to long compile times, having to download libraries or something is a sure focus killer.

And as I said, just idle web browsing is a problem that I should try to take care of. :)

I believe RescueTime will block certain websites for certain amounts of time. So you could keep Pandora open while all other sites are blocked. Although you have to pay $6/mo to get the feature.

If you're on OS X, check out Concentrate:

http://getconcentrating.com/