Her Essie brand, now owned by L’Oreal, is undoubtedly one of the most recognizable names in nail polish and a mainstay for millions of women who get regular manicures. In the U.S. alone, more than 25,000 salons carry a selection of the 250 or so colors that make up the line—including the deep red Bordeaux, one of Weingarten’s initial creations.

A born and bred New Yorker, the 66-year-old grew up in Hollis Hills, Queens with a love for fashion and graduated from the Fashion Institute of Technology in Manhattan. A handful of jobs in the field followed, including working as an assistant buyer in the gifts department at Henri Bendel, but she always wanted her own company. In 1981, Weingarten gathered her life savings of $10,000 and launched Essie.

Within a year, the bottles were in more than 10,000 salons around the country and generating profits; by the time L’Oreal bought Essie in 2010 for an undisclosed sum, the polish company had a presence in more than a 107 countries.

Today, Weingarten lives in New York City with her husband Max Sortino, 59, who was the CEO of the eponymous line before the sale. She talked to Fortune about what inspired her to create Essie, how it got so big, so quickly, and why Las Vegas is the perfect place to launch a nail polish line. The following conversation has been edited for length and clarity.

Fortune: What gave you the idea to start a nail polish business?

Essie Weingarten: I always knew I wanted to have my own company because I come from a family of entrepreneurs. I wasn’t sure what it would be, but I loved getting my nails done. When I was little, my mom used to take me to the salon on Saturdays for a manicure if I was good that week, and I remember that the color choices of the polishes were usually boring. So, I got this idea to create fashionable and high-quality shades—they wouldn’t chip and would last a week to ten days.

How did the line take off so quickly?

A trip to Las Vegas did it. I used the $10,000 I had saved away from working and got 12 colors of polish made at a lab in New Jersey, including Bordeaux which is still part of the line and still popular.

I had to figure out a way to market what I’d created and thought Las Vegas would be perfect because the women working there in the casinos showed their hands a lot. I flew out there and made little kits of all the colors using plastic bags. There were probably about a 100 salons in Vegas back then, and I went to each one and gave them out and told the owners that if they liked the shades, they should call me.

Within a week, every single one called with orders and within a few weeks, I was getting calls from salons around the country. Women who were visiting Las Vegas and got manicures while they were there requested the colors at their salons back home so those owners then called me with orders. Within a year, I was in 10,000 salons, and the next year, I got picked up internationally.

As an entrepreneur, what mistakes did you make along the way?

I made plenty, but I think the biggest one was in the beginning when I didn’t put my name on the bottles. In fact, they had no label until 1999 when we finally got the bottles made with Essie etched on the glass. Branding is key to any business because people want to buy a brand.

I also never advertised when I started because I thought word of mouth was the way to grow. That is true especially today when social media is so prevalent, but our primary market was salons and distributors, not direct consumers, and when we did start advertising in trade publications in 1988, our reach to our target market became that much wider.

Besides learning from your mistakes, what’s the most valuable lesson you learned as your business grew?

Always hire people who are smarter than you and have an expertise in something which is your weakness. For me, it was HR. I had no HR experience at all so I hired an HR manager.

How did the sale with L’Oreal transpire?

The company first approached me in 2005 about buying me, and I said no. Then the recession happened. We were doing amazing business but needed a new facility because we were growing so fast. I was really nervous to make the investment so when L’Oreal came to me again, I agreed. The sale happened on June 25^th, 2010.

Did you retain creative control after the sale?

Up until we sold, I was doing the color development and the naming, but after, even though I was still the creative director, I became part of a team, and it wasn’t my baby anymore. The final decision was no longer mine.

Are you still involved with the brand today?

Let’s just say that I’m here if they need me.

Earlier this year, the New York Times wrote a series of articles on the widespread exploitation of manicurists by salon owners. What are your thoughts on the issue?

Believe it or not, I was never privy to salon culture. I used to deal with salon owners and distributors usually by phone and didn’t know what was going on day-to-day so when I read the articles, I was shocked. I find it horrifying.

What advice do you have for aspiring women entrepreneurs?

Follow your gut and passion, and know that being successful is not a crapshoot. When I started, I worked 24/7 because I was handling all the sales calls around the world myself, and given the different time zones, I was always awake. So, I’d also that you need a 100% commitment. You can’t do it part-time.

Are you bored now not working full-time?

For me, that word doesn’t exist. Max and I go to the theater a lot, we cook a lot, and we enjoy life.