to concentrate on one thing at a time, to GTD
avoid Multi Tasking?
first - care - For as long as you know in your heart that what you’re making or doing matters, and, consequently, for as long as you accept and embrace the immutable laws of ScarcIty, your options for maintaining focus will, like Frank’s perfect answer, remain stunningly obvious.
a single MissIon?
And for everything else, just do the Simplest Thing!
Feature Set/UI: Simon C R Lewis says: Every feature has a cost in that it requires space in the user’s Mental Model of the device. Every additional feature can dilute the impact, understandability, and utility of every other feature, including those which deliver the Core Value.