It's easy for me to get distracted and switch from productive work to just browsing LW or whatever. So I decided that every time I switch to a new activity, whether work-related or not, I will document it: time the last activity stopped, the details of what its status was at the time of suspension, whether the original goal was achieved or not, and any notes relevant for future resumption of it. Also record what the next activity is, it what stage it is at, what the intended goal is, and optionally anything else pertinent. ONLY THEN switch to the new activity. I set no restrictions on what the new activity can be, none whatsoever, just made sure I document every switch. It only takes a couple of minutes at most (I wrote a quick-and-dirty google docs spreadsheet to simplify entering the notes).

So far I have noticed a couple of benefits: I rarely switch to an unproductive or frivolous task, partly because of the hassle of having to document it in advance, and partly because writing down something like "gonna browse some LW forums, cuz I don't want to debug this code anymore" is plain embarrassing. Additionally, I ended up having a reasonably well documented diary, which is helpful when resuming a suspended task some time later.

In retrospect, it's raising the switching threshold that seems to provide the benefit. Apparently also works for dieting. Having to write down what you are going to consume and why, before you ever open the fridge, may reduce spontaneous munching for some.

The part I like is that I put no restrictions, so there is no guilt after due to breaking them. As long as everything is written down, including the motives and the outcomes.