The "No" muscle
This is quote is from one of several articles I've run across recently on the topic of the power of saying "no" more often to opportunities. And I think Kevin says it most succinctly. But I would change "time" to "attention". We can have all the time in the world, but without attention to the important, we'll never ship. So if you apply this principle more broadly to anything that could distract you from creative work, self-control becomes the real muscle you have to develop.
You have to practice saying "no" to many things, many of which are not people, if you want to be creative and productive. And it takes time. After two years of focus, I feel like at least a few good habits are solidified. I've said "no" to notifications on all my devices and desktops, to checking email more than twice a day, to unscheduled and agenda-less meetings, to clients and contractors that don't respect boundaries, and to billing by the hour.
There's still much more work to be done. I need to say "no" more to reading as an excuse for doing, to Twitter as an excuse for anything, to unimportant tasks, to feeling sorry for myself and the unproductive ways I try to cope with it, to giving away too much, to not giving away enough, to valuing career over family, and to worry.
That's me. Where do you want to start?