Christopher Isaac "Biz" Stone, co-founder of Twitter Inc., right, speaks during a featured session at the South By Southwest (SXSW) Interactive Festival in Austin, Texas. (David Paul Morris/Bloomberg)

One of the most important business lessons Biz Stone ever learned dates back not to his days in college, nor to the years he spent building Twitter — but rather to one painful day in middle school gym class.

During a conversation here at South by Southwest on Tuesday, Stone recalled watching other students in gym class perform back handsprings. Inspired, Stone says he mustered up all his strength and tried flipping backwards several times, hoping to replicate the move but instead “landing on my ribs over and over again.”

His teacher eventually walked over and offered some advice, explaining that he simply needed to fall backwards, almost to the point of no recovery, before reaching down with his hands and gently kicking upwards with his feet.

“It’s an incredibly difficult mental maneuver to allow yourself to fall on your spine, and that translated years later to this lesson,” Stone said. “In order to succeed spectacularly, you must be willing to fail spectacularly.”

He says that lesson became a driving principle when he was working with three other entrepreneurs during the early years at Twitter. Of course, a short five years later, the company has exploded and now brings in more than $300 million a year.

Related: Twitter’s Jack Dorsey shares his tips for entrepreneurs

Stone has launched and advised several other successful ventures, and earlier this year he showed off a new mobile app called Jelly that allows users to send images and related questions to their social networks. In the past few months, the company has announced two separate funding rounds (neither amount has been disclosed) spearheaded by some of the nation’s top venture capital groups.

Speaking at the annual film, music and technology festival in Austin, Stone shared a few more insights into his business philosophy and — much like his gym teacher did decades ago — offered some helpful hints to future entrepreneurs.

1. Start by delivering value, then figure out how to make money

“It’s actually cart-before-the-horse to start by working on a business model when you only have a small number of people, because you first need to build a product that you can prove is of value before you try to monetize it,” Stone said. With Jelly, he added, his entire focus right now is on “building robust technology.”

2. When possible, bring lots of people together

Stone argued that “the role of the entrepreneur is to just get people together and build tools that will help them do good for the world. Often, the role of the entrepreneur is just to assemble the group.”

3. You can’t always predict how your product will be used — and that’s okay

“The initial vision was being able to see what your friends were up to, and that was good enough for us,” Stone said. “But then all of these things started happening. A simple tool we had built started to have hundreds of unintended consequences.”

Note: In an apparent (and ill-timed) coincidence, Twitter crashed partway through Stone’s conversation with author Steven Johnson, leaving many in the audience struggling to send tweets about the event (several turned to Facebook to share what was happening). Clearly unaware of the outage, Stone and Johnson continued to ask the audience throughout the event to tweet questions they would like answered using the hashtag #askbiz. At least a few tweets apparently made it through before the crash and were addressed quickly before the panel concluded.

To follow our ongoing coverage of start-ups, entrepreneurs and technology at South by Southwest 2014, click here.

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