Another good article (despite the title which I fear may send people down the wrong mental path)
Please Stop Complaining About How Busy You Are - Meredith Fineman - Harvard Business Review
The main message; that there is a distinction between working hard versus smart, is spot on.. But there's more depth to be had in this article than than a glib statement of the obvious.
I'll paraphrase, but one of the best observations Meredith makes is that she used to be a swot and that she used to diligently grind through all the detail:
One of my greatest lessons as a businessperson has been to throw out that skill set. This isn't to say you shouldn't be diligent or that you should half-heartedly execute, but rather, that it's crucial to know what you have to do as opposed to everything you could do. It's about being strategic.
Work smarter - not harder is about unlearning some of the skills and habits that made us successful, that got us so far, but will actually hold us back if we don't adapt.