I've been thinking about how to write this post. I think it's an important topic, but easily misunderstood. "Do less" doesn't mean be lazy, it means focus. Pick one thing you're really good at and make yourself an expert at it: world-class. It doesn't matter what you pick, just be the best. Be it marketing, dance, or winemaking. If your domain is playing Bolivian panpipes, then make yourself the best that the world's ever seen.
I used to work with a smart and upcoming e-mail marketer. Part of her job was to liaise with the designer on creating the e-mail templates. The emails are written in HTML code, and she would often tell me she intended on learning the basics of HTML so that she could be "useful" there. She was really good at marketing, particularly direct response (e-mail, search engine marketing etc), and was on a path to becoming the best I'd ever seen. If she had spent her nights and weekends learning to code, at best she was destined to become a mediocre coder, and it would likely result in the trade-off of her not reaching her potential in what she could excel at.
I'm hardly against people learning how to program -- in fact, I think it's so important that it should be taught in schools -- I just think that people need to be resolute enough to admit who and what they are, and then tenacious enough to pursue their goals systematically.
Seth Godin talks about this in his book The Dip. The latter part of the title sums it up: "A Little Book that Teaches You When to Quit (and When to Stick)." The basic premise being that most people give up when the going's tough, and instead we should either give up before it even gets hard, or persist through it.
"Well-rounded" used to be seen as a positive. It's now a millstone of blah mediocrity. I'd rather be exceptional at one thing than average at 10.
As a winery, the goal of "making the best wine" is too nebulous to be useful. So pick something specific... and dominate it.
And me? I'm never going to be the world's best "marketer" -- I don't even know what that means. Instead, I'd rather aim to be the best "U.S.-focused online-enabled wine social commerce marketer." Not that my mother or half my friends know what that is, but it's what I think I'm good at.