I like to throw some pomodoros in each day. I feel that at first it is a tad awkward. However, after you get used to it, you feel the need to really finish a unit of work in the allotted time. I feel that the pressure to get into the zone quick and practicing it helps. For those unfamiliar: pomodoro is 25 minutes uninterrupted work, 5 minutes break. Rinse, repeat.

I like using pomodoros periodically. I find that I don't always need them, but if a day or two goes by where I'm feeling unfocused, using them for a couple of days gets me back on track.

I like to add in some noise canceling headphones into the mix to help with the interruptions while trying to execute a pomodoro. A cold hard stare helps too :)