Slow down and remember this: Most things make no difference. Being busy is a form of laziness—lazy thinking and indiscriminate action. Being overwhelmed is often as unproductive as doing nothing, and is far more unpleasant. Being selective—doing less—is the path of the productive. Focus on the important few and ignore the rest. Of course, before you can separate the wheat from the chaff and eliminate activities in a new environment (whether a new job or an entrepreneurial venture), you will need to try a lot to identify what pulls the most weight. Throw it all up on the wall and see what...