To me, working "smarter" has always been about recognizing where the "leverage" is in your business and taking advantage of it.
At the end of the day, there are some businesses that simply don't have an obvious or easy "leverage" point. Lawyers and dentists and doctors can only bill so many hours in the day. They are fundamentally limited in their earning potential by the clock. The "leverage" point becomes a practice, where they build a book of business and take off the top from the billing hours of employees.
A taxi driver has very little "leverage" to speak of.
Software, on the other hand, has an incredible amount of leverage: distribution is cheap; the marginal cost of customer acquisition and maintenance tends to be much, much lower than other businesses; initial capital costs are much lower than other businesses. That's why you get rags-to-riches stories in software more than other places: home-runs are cheaper to swing for.
In the taxi-driver business, it is hard to define "smarter." Points of leverage probably include discovering the optimal locations and times for maximize fares-per-hour. Ultimately, you're bound by the number of hours in the day, and that is a tough business to leverage. When there is no leverage, it is tough to work smarter; often, you have to resort to working harder.
Think about Coca-Cola. What is the core asset? Certainly they have developed a brand, but they protect their formula as trade-secret. Coke could theoretically be run as a pretty small organization, maybe just an IP holding company, and leverage bottling and distribution companies to take advantage of their already existing infrastructure. To me, that is working "smarter." That is what a lot of software companies do. Look at all the "bottlers" and "distributors" that are coming out of the wood-work for software. For a start-up, I can pretty much out-source (from open-source, nonetheless) the majority of my components, IT infrastructure, and IT maintenance. That is leverage. That is working "smarter."