For serial entrepreneur Stacey Ferreira, 23, the Millennial generation is best defined by this Napoleon Hill quote: "If you're not learning while you're earning, you're cheating yourself out of the better portion of your compensation."

More than anything else, she says, Millennials are seekers of purpose.

Ferreira, who heads up the digital advertising agency AdMoar, took the stage Thursday morning at Inc.'s annual Women's Summit in New York City along with Rodney Williams (31), co-founder and CEO of Lisnr, Sols co-founder Kegan Schouwenburg (29), and Inc. senior editor Christine Lagorio to discuss what really defines this generation at large.

Accounting for as many as 80 million people between the ages of 18 and 34--and an estimated $200 billion in U.S. spending power--Millennials are clearly a valuable demographic to businesses and employers.

Still, it's difficult to pin this group down. It's the most ethnically diverse generation to date, according to 2014 research from the Pew Center, as well as the most educated. And here's grim news for advertisers: Nearly half (48 percent) of Millennials say that word of mouth is their biggest purchasing influence, and just 17 percent say that an ad has ever prompted them to buy something.

So what's the best way to appeal to these hard-to-define consumers? Below, three expert tips from founders who know them best:

1. Focus on authenticity.

Ferreira is precocious, to say the least. She started her first business, mySocialClub, at just 18 years old, before selling it to in 2013. She has started two subsequent companies, content marketplace AdMoar and Forrge, a website for contract and freelance job-seekers. She also co-authored the book 2 Billion Under 20: How Millennials Are Breaking Down Age Barriers and Changing the World.

Her biggest piece of advice to business owners wanting to target these customers has to do with making sure you really know what they want. "Ask how you can be more authentic," she said, adding, "It's about reaching those Millennials where they are."

In acquiring customers for her most recent digital venture (Forrge), Ferreira says she physically travels to college campuses, participates in local community events, and is aggressive on social media.

That same attitude, it's worth noting, should extend to the workplace. Ferreira, Schouwenburg, and Williams all agree that Millennials are driven by purpose.

"Give them a project, and let them feel like it's their own," Williams added. A sense of ownership is what makes Millennial employees go the extra mile.

2. Ditch traditional marketing.

Williams puts it bluntly: "Marketing is not real," he said. The product is what really matters.

Millennials are not likely to respond to advertisements that feel contrived. Schouwenburg, for her part, says she hates banner ads and--even worse--blatant targeting.

"If you have a product and it's good, at the end of the day, that's the company [that will stand out,]" says Williams. "Not the company that's doing marketing."

3. Make something that helps Millennials to connect.

Panelists agreed that one of the biggest misconceptions about Millennials is their being self-absorbed.

Sure, Millennials may be glued to their smartphones, but that makes them more connected to reality, not less, the panelists said.

"We want so desperately to connect with the world, and sometimes technology is the only outlet we have," said Ferreira.

If you really want to reach Millennial customers--and talent, for that matter--create a product and an organization that's giving back to the greater good. Then, be sure that you're communicating your goals clearly and authentically.