Billionaire Warren Buffett has offered investment wisdom for five decades at the annual Berkshire Hathaway shareholder's meeting. Buffett didn't disappoint the 40,000 shareholders who attended this year's meeting, often turning questions about the stock market into tips for a successful life.

During the six-hour question and answer period, Buffett was asked twice to name the single best investment he would recommend today as a hedge, or protection, against inflation. While the two people who asked the questions expected a stock tip, Buffett gave what he considered a far more valuable opinion.

"I'll tell you something even better than one stock," Buffett said.

"The best investment--by far--is developing yourself"

If you are exceptionally good at something, people will beat a path to your door, says the 91-year-old investor. If you develop the skills that others are willing to pay for, you'll thrive despite what's happening in the broader economy. According to Buffett, "Your abilities can't be inflated away from you."

For years, Buffett hosted business school students who made a pilgrimage to his office in Omaha to meet with him. The students were often surprised when Buffett showed off his most prized diploma--a framed certificate from a public-speaking course.

"I have one diploma hanging in my office," Buffett would tell them. "It's from a Dale Carnegie course, which cost me a hundred bucks back in 1951. It's incalculable how much value I got from that hundred dollars."

There's nothing like working to improve your own skills, Buffett said. He then added, "I would say communications skills are the first area I would work on to enhance your value throughout life, no matter what you do, because if you can't talk to people, you'll have a real problem selling anything--stocks or anything else."

Buffett has a point. Regardless of your title or position, you're in the business of selling something. Job candidates are selling their skills. Entrepreneurs are selling their ideas. Small-business owners are selling a product or service.

If you take a public-speaking course, that's fine. But I call this the golden age of public speaking because of the vast amount of free resources available at your fingertips.

1. TED Talks

An average of seven TED Talks are given every day. Thousands of individual presentations are streamed for free on the TED website. When I wrote Talk Like TED, my book wasn't intended to show people how to get on the TED stage. Instead, it was based on lessons that anyone can learn from some of the world's best public speakers.

When you watch TED talks to improve your public speaking skills, pay attention to what speakers do differently. You'll find that most begin with stories, a powerful technique to hook an audience. You'll see slides that are very simple with minimal text. These are all tactics you can incorporate into your presentations.

2. Product launches and public presentations

Today's top global business leaders launch products, make speeches, or give televised interviews archived on their websites or YouTube.

On YouTube, you can watch some of the best product launches in business history. My personal favorite and the one I recommend to clients is Steve Jobs's 2007 introduction of the iPhone. It still holds up as one of the best business presentations of our time. It has everything--an exciting product, a charismatic speaker, suspense, humor, stories, demos, and gorgeous slides.

3. Talks at Google

Google invites experts from a variety of fields to talk about their secrets to success. Many of these talks focus on communication skills and public speaking.

I've given five Talks at Google on topics like storytelling and presentation skills. You can also watch leaders like former PepsiCo CEO Indra Nooyi talk about skills like public speaking, which she considers "foundational" to a great career.

There will always be something that people worry about: inflation, recessions, international conflicts, falling stocks, etc. But no one can take away your skill. If you're good at public speaking, it will set you apart, making you irresistible and irreplaceable no matter what's happening in the world around you.