David A. Steinberg was riding high when his wireless phone company, InPhonic, earned the No. 1 spot on the 2004 Inc. 5000 on annual revenue of $119.4 million. Three years later, Steinberg left, and InPhonic filed for Chapter 11. But he didn't sit still. That same year he launched marketing technology firm XL Marketing (now Zeta Global). Here, Steinberg reflects on what went wrong with InPhonic--and how he's doing things differently this time. --As told to Christine Lagorio-Chafkin

I started my first company at 16. Now I'm 52, and what comes with maturity is the understanding that I don't need to prove myself every hour of every day. When I was a young entrepreneur, I thought I had to do everything. I had to be the head of every division and know every detail. But when you have your hands in every single thing and are telling people specifically what to do all day long, not only are they not going to do their best, but you're not able to recruit the best people, either.

Today, my focus is on my company's strategy. That includes hiring the best people and coaching them--not controlling them. I let people know it's OK to fail and to ask questions. But I'm not doing their jobs for them. That would inhibit their growth.

Having the best people and seeing them grow is the foundation of a much more stable business. Zeta Global has now become one of the world's largest data-analytics com­panies, with 1,000 global clients and 1,300 employees in 15 offices in 11 countries. And we are newly listed on the New York Stock Exchange. It's such a difference from the last time around.