The used-furniture marketplace AptDeco began with a simple rule: Safety first. 

In 2012, after graduating from business school, AptDeco's co-founder Reham Fagiri saw the dark side of selling furniture online. She was moving from Philadelphia to New York City and had put an ad on Craigslist.

"I had this guy who came to look at my TV, and he got really frustrated with me in my apartment. I was a single woman at the time. I didn't have a doorman, and I was alone," Fagiri said in a recent interview streamed onInc.with Beatrice Dixon, co-founder and CEO of Atlanta-based feminine-hygiene business the Honey Pot Company. "And he's like, 'I came from like the suburbs of Philly and I'm really frustrated, and, you know, I'm just gonna take it.' "

The moment triggered something inside of her. She felt unsafe in her own home and knew there had to be a better way to sell her furniture. So, in 2013, she co-founded AptDeco with the goal of making the buying and selling of used furniture online simple and safe. Here are three things Fagiri did to build and grow her business.

1. Walk the talk.

Fagiri was an engineer by training and had climbed the career ladder at the investment firm Goldman Sachs before heading to graduate school to earn an MBA. She says it was important to learn every aspect of the business as much as she could. When AptDeco first launched, she made many of the pickups and deliveries herself. Now, she says, "we have our own trucks and drivers and a lot of amazing team members who do the heavy lifting, literally and figuratively, every day."

But this doesn't keep her from getting her hands dirty. She still goes on ride-alongs with her delivery team and is at her operations facility all the time. "I'm on the ground, learning and seeing, and also getting to know the team," she says. "No matter how big we get, it's important to really learn firsthand, versus hearing it from a lot of different sources."

2. Follow the data. 

One way AptDeco has been able to drive growth, Fagiri says, is by listening to what its data says. When the company began to study its customer data, it found that certain brands were very popular.

Fast-forward to today, and now AptDeco has partnerships with several large retailers, ensuring it always has the brands that people are looking for. Fagiri says she is constantly examining customer data. "What we see is people who use AptDeco usually come back a lot more frequently than the average furniture buyer," she says.

3. Focus on what you can control.

You're likely to face a myriad of distractions, ranging from competitors' strategic moves or news about startup fundraising trends. Don't let them take your eye off the ball, says Fagiri.

"It doesn't faze me what happens out there, because I know I'm building something that is going to last, and I'm very proud of that," she says.