Successfully starting and running a business is a difficult challenge. Long work hours that detract from one's social and family time, financial pressures from unreliable income, repeated rejection from prospects and investors, and the inevitable accompanying emotional roller coaster all create an uphill battle that few wish to fight–and far fewer actually win.

Young entrepreneurs face additional challenges that can make their path toward entrepreneurial success even more difficult. Employees, prospects, investors, partners, and pretty much everyone else with whom a businessperson must deal, for example, may not trust young entrepreneurs due to a perceived lack of experience.

Learning from people who succeeded as young entrepreneurs, is, therefore, especially important for people starting businesses before they have built up years of professional experience. Below are some points of advice from several entrepreneurs who successfully built businesses before they were 30:

David Adelman, President & CEO of Campus Apartments, developers, owners, and managers of student housing, of which he became CEO at the age of 25:

Listen more than you speak in business settings.
Learn from your mistakes.
Stick to your strengths.

Gregory Galant, who founded Halenet, a website development business, when he was 14, and is now the Co-Founder and CEO of Muck Rack, a platform used by columnists (including myself) to showcase their writing and by businesses to get press and manage public relations, and the Co-Creator and Executive Producer of The Shorty Awards, the "Oscars" of social media:

Pick an emerging industry.
Provide an awesome product or service to your customers.
Get PR!

Geoff Gross, Founder & CEO of Medical Guardian, a provider of Personal Emergency Response Systems, which he founded when he was 25 and has since grown to over a hundred employees:

Know your customer.
Lead by example.
Be brave, and speak up, carefully.

Chris Wilkerson, who founded Pachysandra Plus, a plant nursery, which he ran for over a decade after founding it when he was in ten years old, and who is currently the Senior Managing Partner of Praxis Summit, a cloud-based performance improvement platform.

Look professional!

What do you think? Please feel free to discuss with me here or on Twitter.