These 2 Simple Ideas Helped Rodan + Fields Become a Billion-Dollar Brand The developers behind Proactiv, Dr. Katie Rodan and Dr. Kathy Fields, share their success strategies and routines.

This story was originally published on August 31, 2017 and has been updated.

Editor's Note: Entrepreneur's "20 Questions" series features both established and up-and-coming entrepreneurs and asks them a number of questions about what makes them tick, their everyday success strategies and advice for aspiring founders.

In 2002, Dr. Katie Rodan and Dr. Kathy Fields founded Rodan + Fields, a skincare brand built on the promise of offering consumers innovative anti-aging skincare products that are backed by clinical results. With a reported net revenue of $1.15 billion in 2016, the concept, it would appear, is working.

In addition to founding R+F (and maintaining their medical practices), the doctors also developed the acne treatment powerhouse Proactiv. In April of 2016, they reportedly sold their royalty rights for an estimated $50 million, and in 2017, R+F was named the No. 1 premium skincare brand in the U.S. by market research company Euromonitor International Limited.

We caught up with busy founders to ask them 20 Questions and find out what makes them tick.

1. How do you start your day?
Katie: Ideally, I'll squeeze in a workout on my Peleton bike; it gives me energy mentally and physically. Starting the day off with a routine makes all the difference in preparing for my day ahead, which is never routine.

Kathy: I wake up and meditate for 15 minutes, then check the news. I also do a high-impact 25-minute workout and stretch before heading out for the day. This routine helps me get energized and stay focused throughout the day.

2. How do you end your day?
Katie: For as long as I can remember, I have had trouble falling asleep. My solution is to take Valerian root and melatonin nightly. Before these herbs kick in, I catch up on my reading, whether that's a business psychology book or a novel.

Kathy: In the evening, I catch up on reading – sometimes from up to 16 sources. What I read ranges from medical news across all specialties to philanthropy, politics and daily news. I like to compare sources to really discern the truth about what's happening in the world.

3. What's a book that changed your mind and why?
Katie: Growing a Business by Paul Hawken, which I read back in 1988. Paul started his business, Smith and Hawken, a garden lifestyle brand, with very little capital. He points out that bootstrapping a business forces you to think creatively in deploying resources, and relying on your resilience will take you to the finish line. His book gave me permission to go for it. Back in 1989 when we had the idea for Proactiv, Kathy and I were young and just out of residency -- with Spartan bank accounts -- and not an investor in sight. We learned to be disciplined, think outside the box and set financial priorities to launch our first company.

Related: This Introvert Founder Swears by This Management Tip

4. What's a book you always recommend and why?
Katie: The Innovator's Dilemma by Clayton Christensen. He coined the term "disruptive innovation" more than 20 years ago and wrote about how the "little guy" can shake up an entire industry. We encourage entrepreneurs to not only look for opportunities to disrupt, but once your business is established, think a step ahead to prepare for the next disruptive innovation that could threaten your company.

Kathy: I recommend Blue Ocean Strategy by W. Chan Kim. It speaks to important questions that are key to ask in the early development of your idea – questions that must be addressed early on, or you could be done with your business before you even get started. These questions are critical to success.

5. What's a strategy to keep focused?
Katie and Kathy: Pure and simple -- it's about purpose. Our purpose has always been giving people the best skin of their lives, whether it is through our dermatology practices or the two businesses we started, Proactiv and Rodan + Fields. We know how critically important a great complexion is to one's self-esteem and confidence. Because we believe that the purpose of our business serves the greater good, focus, hard work and persistence have always been part of our daily lives helping us to overcome obstacles and compelling us to create products that deliver professional level results.

Our advice to entrepreneurs is two-fold: Always do the right thing. When it comes to the people in your life, you never should compromise your ideals or your integrity for personal or financial gain. Your reputation is everything.

Put your aces in their places. Bringing your entrepreneurial vision to fruition takes a team of smart and experienced people. Find them, trust them and empower them to help you make decisions and take decisive action, which will help you build the business of your dreams.

6. When you were a kid, what did you want to be when you grew up?
Katie: I always wanted to be in business for mysel, and recognized this ambition at a young age -- starting with Girl Scouts. One year, our troop sold so many cookies, we won a trip to Disneyland. Instead of riding the rides, I spent the day outside the ticket booth selling each individual ticket. My parents couldn't believe it when I came home with a pocket full of money. A couple of years later, around age 13, I started a small business creating and selling purses and beaded necklaces to a retail shop. In a few years, I made enough money to buy myself a car. These early experiences rewarded me for being resourceful and fueled my fire to seek an entrepreneurial path.

Related: Use This Founder's Top Tip To Make Your Meetings Work For You

7. What did you learn from the worst boss you ever had?
Katie: Intimidation never works. This lesson taught me the value of being approachable and providing an environment that encourages open, honest discussion.

Kathy: Don't avoid confrontation. Confrontation happens and you have to learn to deal with it. It's always hard, but running away is not the answer. Confrontation can still be uncomfortable for me, but it's important to be able to address difficult topics and talk about different points of view.

8. Who has influenced you most when it comes to how you approach your work and why?
Katie: My father. As a young girl in the 1960s, I was lucky to have spent a lot of time with him when my mom went back to graduate school. Our dinner time conversations and the words of wisdom he gave me through stories of his extraordinary life as a depression era kid, a UCLA student body president, a Marine in WWII, and a federal judge, guide me until this day. I learned from him "when the going gets tough, the tough get going." I was encouraged to "be my own boss, make my own money and determine my own destiny." And, I was inspired by his work ethic, compassion and indefatigable determination to help those in a less fortunate or powerless position.

Kathy: My parents. My dad was an ophthalmologist and he went to work with joy and purpose. He wanted us to be our own boss and to be able to change others' lives. He always encouraged us and demonstrated first-hand the importance of being reliable, honest, accountable and having high integrity.

9. What's a trip that changed you?
Katie: I went to Scandinavia with my parents when I was 13. On that trip, I met a Norwegian boy who had just run away from home. We stayed in touch, and he came to California many times over the years that followed. After meeting my uncle, a self-made real-estate developer, my friend moved from manufacturing sweaters to investing in the burgeoning Oslo real estate market, eventually becoming one of the most successful people in his country. This experience taught me to always be open to meeting new people from diverse backgrounds. You learn so much from each other, and you never know the impact you can have on their life and vice versa.

10. What inspires you and why?
Katie and Kathy: We're inspired by our patients to make products that deliver life-changing skincare results, our families and each other. Doing the right thing. Taking the high road. Executing to that goal every time is one of our guiding principles.

Related: The Founder of Bumble Reveals How the 'Question of Nine' Can Help You Stay Focused

11. What was your first business idea and what did you do with it?
Katie: My first business started at age 13, selling purses. I was inspired after seeing a purse that I loved but couldn't afford at a trend-setting store for teenagers in Los Angeles. After learning to source the materials wholesale I used my sewing skills to figure out how to design and make the purse even better. I ended up supplying a store called The Light Brigade with my purses until I went off to college.

12. What was an early job that taught you something important or useful that you still use today?
Katie: From my first days as a medical student rotating through the obstetrics ward, I learned the meaning of trial by fire. In my case, how to respond to a pressure-cooker situation when you lack the skills or confidence to do so. After watching a first-year resident deliver a baby, I was told to deliver the next baby on my own! Terrified as I was, I managed. By the end of my rotation, I was teaching the next group of incoming students the skills I had acquired. The principle, "see one, do one, teach one" carries forward today in our business model. Our incoming Rodan + Fields consultants learn from our field development corporate team and other successful consultants how to build their business and service customers with excellence and pride.

Kathy: As a kid I would help clean the mirrors in my dad's ophthalmology office on the weekends. He was very proud of the work he was doing to improve lives and give people vision. He had a sense of purpose, and it was a lot of fun! He taught us to be independent.

13. What's the best advice you ever took?
Katie and Kathy: Surround yourself with the best people, and make sure it is people with diverging views. And listen to them and trust them. It doesn't mean that you're going to give them carte blanche, but you have to realize that there is no way you could know everything that you need to know to do your business. Focus on where you are strong and put others in place where you need support and are not the expert. Know when you are in over your head.

14. What's the worst piece of advice you ever got?
Katie and Kathy: We were once advised to not move forward with the Proactiv contract. We're glad we did not listen.

Related: This Beauty Founder Shares the Secret Leadership Skill to Making a Company Thrive

15. What's a productivity tip you swear by?
Katie: Make a written list and abide by the adage "done is better than perfect."

Kathy: Find an accountability partner. We've been lucky to have each other as partners who share the same goals and burdens.

16. Is there an app or tool you use in a surprising way to get things done or stay on track?
Katie and Kathy: We both use the standard notes app on our phones for updating our to-do lists in real time, going back to the importance of writing things down.

17. What does work-life balance mean to you?
Katie: For me it all blends together,r and I've stopped trying to separate the two. Because I have family and friends who work in our business along with employees and consultants I dearly love, I have as much fun at a work-related event as I do on vacation. Fortunately, I inherited a good dose of my mom's energy, so working hard, playing hard comes naturally.

Kathy: Both family and work should give you great satisfaction. If something is not working, find out where the problem is and do something about it so you don't repeat the same thing. To truly achieve work-life balance, you have to sacrifice the things that are not working for you.

18. How do you prevent burnout?
Katie and Kathy: Go off the grid every once in a while. We both try to unplug, spend time with family and travel when we can.

19. When you're faced with a creativity block, what's your strategy to get innovating?
Katie: I go on a hike without my cell phone or any music, letting my mind freely wander to receive ideas and solutions from my subconscious.

Kathy: Brainstorming! It is tremendously stimulating to get in a room with a group of people with different points of view and throw out ideas. For me, the wheels start turning when there's a lot of people in the room pooling ideas from different genres. It's very stimulating and a lot of fun.

Related: Stitch Fix Founder Explains Why the Worst Piece of Advice She Ever Got Was to Raise A Lot of Money

20. What are you learning now?
Katie: I've taken up a private study with an art history professor. Through art, you learn to see the world through a different lens. As for my business practice, art helps focus the creative part of my brain.

Kathy: I am interested in learning more about board governance – all aspects of it, from technology to compensation. I've been learning on the job and now comes the hard part – class work.