A shift in perspective is old news. It takes a frustrating amount of mental energy and is often done grudgingly--like showing your work in math class. Besides, it's usually at the behest of so-called good advice, and really, when is that last time following advice had a lasting effect?
No, what we need is a shift in consciousness--a simple stilling of the noise of the inner waters and a fuzzing out of the gaze, letting what's out there rush in to fill that raw, churning, gnawed-on space.
Filling an empty glass is as easy as dropping it into the stream, and as much as we think we're filled to the top with our worries/fears/obsessions/possessions/problems/workload, we're not.
Thinking we're full is the first sign we're dangerously close to running on empty.