Six and a half years ago, John Thies, along with his sister and co-founder, Michelle Klann, first formulated the idea for a company that would later become Email on Acid — a platform specifically devoted to optimizing and testing email marketing campaigns. Today, the product allows customers to preview emails on 44 different clients and mobile devices and test those emails against 23 spam filters and 72 of the most common blacklists. With more than 80,000 customers, Email on Acid has transformed from a part-time business into a full-fledged technology platform.

In this exclusive interview, John reviews eight of the most important lessons he’s learned over the last six and a half years.

1. Find a Need in the Market

Inspiration for Email on Acid came from the consulting business John, a back-end developer, ran with his sister, Michelle, a graphic designer. Client after client came looking for help with email design and development. Customers would then take the beautifully designed and coded emails and send them through third-party email providers only to discover problems with formatting and functionality. John and Michelle found that aspects of their designs didn’t translate over to certain email clients. And, while there were products out there that allowed users to test and preview design, none of them went deep enough.

“We decided the market — and our customers — needed a tool that would actually dig through email code and pinpoint exactly what was and wasn’t supported by specific email clients. That’s where the idea for Email on Acid came from. Now, did we have any idea that it would become what it is today? Absolutely not.”

2. Take Risks

John and Michelle both took huge risks to give up their lucrative consulting business by putting everything they had into Email on Acid, but in the end it paid off.

“It was very difficult,” says John. “But, you know, you have to take risks. Michelle and I were definitely entrepreneurial types and never envisioned having the same job or doing the same thing over and over for the rest of our working lives, that’s why consulting was the perfect opportunity. Prior to our consulting business, I’d been working for the government, but decided to leave because I couldn’t handle all the red tape. I needed something that would challenge me. The transition to consulting was scary, but it was worth it.”

But, as their business grew and the idea for Email on Acid further crystallized, Michelle and John started devoting more and more time to developing the platform.

“We were of the mindset that we would just see how things progressed. Then as we started getting attention and attracting paying customers, we ramped things up further. Of course our steady revenue stream from the consulting business made things a little less riskier — it wasn’t like I had to quit my full time job, but we were dedicating all of our remaining waking hours to Email on Acid.”

Running a business no matter what kind of cushion you have entails putting a lot on the line. John knows that not everything he and his team come up with will be a success, but taking risks in the first place can be small victories of their own.

“We fail often and we fail fast. We find those couple of things that stick — those that have really taken off. And in the end, we wouldn’t recognize the winners if we didn’t fail all those times before.”

3. Build Your Product on Technology that will Allow You to Scale

Like any business, Email on Acid has evolved over time and John has learned many valuable lessons along the way. Unfortunately, when it came to the cloud, John learned things the hard way.

“Had I known better, I would have put all of our hardware on Amazon right from the start,” he says. “Unfortunately, we had different mindsets at the time. We wanted more control over our hardware and back-end computing.

“Now looking at it, it was kind of a waste. I’d say 95% of our technology is up in the cloud today. And it’s a godsend. I sleep so much better at night knowing that someone else is taking care of that for us. With everything in the cloud we can quickly scale to any capacity.”

4. Surround Yourself with People Who are Smarter than You

Having built his business with his sister Michelle from the start, John understands the value other team members can add. He’s made a point of surrounding himself with not just A players, but with people who are smarter than he is and have deep expertise in areas where he does not.

“I try to surround myself with people smarter than I am. You don’t grow if you aren’t constantly learning something new or getting a different perspective on things. We want our colleagues to be a part of our family, not minions or just cogs in the wheel. I want them to be involved and I want their input on all aspects of the business, from support up to high-level strategic decisions.

“If you don’t listen to the ideas all of your team members are putting forward, then you’re really selling yourself short. We maintain an open environment, which has enabled us to come up with some of the greatest ideas and innovations we’ve had for the product.”

5. Your Customers are Your Best Source of Inspiration

While many of the best ideas for Email on Acid come from within the company, John has also found his customer base to be a great source of not only feedback, but true inspiration. But, as with all things, when it comes to incorporating customer ideas, there has to be a balance — customer input must be weighed against the company’s own goals and vision.

“I love customer feedback, whether it’s good or bad, because it’s the only way to truly know how well you’re doing. This is precisely why I’m constantly engaged with my teammates who are on the front lines, those who have direct interaction with our customers.”

And no matter how inconsequential a piece of feedback or idea might seem, John takes every bit of advice to heart.

“If just one person has an idea, it’s possible that hundreds of people might benefit from the product tweak that could come from that idea. Our team truly believes that any feedback is good feedback, so we look at everything objectively and continuously ask ourselves how we can be doing things better. Is it the be-all, end-all? No. But if more than one person mentions it, then hey, we might be on to something. It might be worth investing the time and money to make the change.”

6. Hire for Culture Fit

Despite the growth Email on Acid has experienced over the last few years, John is still very involved with hiring. The company is, after all, a family business so maintaining a family culture is a top priority.

“I’m definitely very involved when it comes to hiring and culture is our top priority. We hire on the 60/40 model meaning we’ll hire 60% on a cultural fit and 40% based on skill level. We have teams in place that can teach people how to do the job but we can’t teach someone how to be a cultural fit. We can’t teach a potential teammate to joke around with their colleagues or to appreciate the open environment we’ve built. It’s loud, it’s noisy, there is a lot of interaction. There is a lot of feedback, but that collaboration is really what we’re after.”

7. Family Makes a Great Coworker

A big part of Email on Acid’s culture comes from its roots in family. But a brother-sister duo is far from typical in most startups. Again, maintaining the working relationship is all about balance.

“Working with family definitely has its ups and downs. The biggest thing we have to keep in mind is that when we’re in the office, we’re colleagues, we’re not brother and sister. That’s something we’ve really had to get used to. We still have our disagreements, but I love her to death and I wouldn’t want to be business partners with anyone else. I trust her more than anything and I think you can really only get that kind of trust with family.”

8. Love Your Business

At the end of the day, John is truly passionate about what he and his colleagues are building. And perhaps his best piece of advice to any would-be CEO is to do what you love and build a team that you love working with.

“I’m constantly inspired every day by the people around me and what they bring to the table. Knowing that what we build is saving people time and frustration is truly my biggest motivator. I love coming into work every day. I wouldn’t trade it for the world. It’s always been my dream to help run a start-up company. It’s definitely exciting to see the business grow and evolve.”