I think a lot of people, myself included, work most efficiently when they’re up against a tight deadline. This phenomenon has been observed both by Aesop (the fable of the tortoise and the hare), and Parkinson (“Work expands to fill the time available for its completion.”)
In short, the more time you have in which to complete an article, the less likely you are to spend all that time on writing the article. It stands to reason, therefore, that in this sense, the less time you have, the better.
Something I have found to be very effective here is a self-imposed deadline, aided by technology (of course!). I use an application called TimeLeft when working on my computer at home, and Chronolite when out and about with my iPad. Each is free, and can be set to alert you when a designated period of time has elapsed.
I’ll be the first to admit that this is bizarre, but I do find that knowing I’m going to be given a metaphorical tap on the shoulder by an application on my desktop makes me write furiously.
I don’t always complete the article in the time I set myself – but this approach works often enough for me to be able to recommend it wholeheartedly!