The mantra "Do one thing well" has been made popular by... I'm not really sure. It's popular, and it's a great mantra, as far as mantras go. But it's really hard. It's risky. It's extreme. A lot of us aren't ready to do One Thing really well at the expense of everything else. I'd like to propose an alternative.
One Less Thing.
Instead of taking a huge leap and focusing on only One Thing, try thinking One Less Thing. Apply that simple phrase to everything that you can think of. Do you have three computers that you juggle, trying to keep your data in sync? Use one less. Get rid of one and simplify.
Do you have 5 major tasks scheduled for tommorow? Cancel one. Put your extra time and energy into the remaining four and end up with much better results. Or take the extra time and spend it in a hammock. The extra rest will probably do you some good.
Have ten books1 on your reading list? Cross off just one. Taking care of three pigs? Time to fry up some bacon.2 You get the idea. One less thing. It's not drastic. It's simple. Start now.