When I experience some bad productivity days, I usually fall back to the Pomodoro Technique. Setting the timer and focusing my mind to the next 25 minutes and nothing else is something that relieves me. No distractions. Just one task for the next minutes. No way to fall into the zone and realize that I have been working on this thing for 3 hours, where I possibly should have taken the time to rethink my solution and if I'm still solving the original problem.
All this time I had been wondering why some days were good and some days were bad without having a solid definition of what a day is.
This is something I can very much relate to. Often I struggle to define what a good day was. It's just my feeling that makes that decision for me. Without having a goal, you cannot say if you reached it. We tell our clients and project managers that it's hard to estimate the physical time a creative task might take, why do I enforce that flawed technique on myself to define a productive day?
I'll try this method for some time now: use the Pomodoro Technique on a regular basis and he number of Pomodors I complete will define the good and the bad days. If the number is to low I should do something about the distractions or re-estimate what qualifies for work in a 25 minute timer. If I do too many, I might have to increase my personal goal, or reevaluate if I just work too much.
In theory it's the original idea behind the Technique, in practice I never thought about it that way.
Thanks Anselm and his WDRL 164 for the link to Jordan's article.