Tony Fadell may be remembered for designing Apple's iPod, but he's arguably even more proud of his second act--he succeeded in making the household thermostat both more efficient and less of an eyesore.  

In 2010, Fadell founded Internet-of-things company Nest, whose smart thermostat product might have seemed a strange device to come from the father of a revolutionary product like the iPod. At a conference hosted by Fast Company in New York Tuesday, Fadell talked about why he pursued designing a new version of a mundane product, and shared tips for other designers. Here are three takeaways from the conversation. 

1. Take a quiet period.

After leaving Apple, Fadell traveled the world for a year and a half before settling on his next product idea, but the trip wasn't just an extended vacation. Fadell needed a "quiet period" between his design projects to gather inspiration, and he advises other designers to seek similar breaks, rather than jumping from one design experience to the next. "I had to pull back and get out of Silicon Valley to gain perspective and see the world in a different way to then re-enter it to be able to do Nest," he says. 

2. Make pain killers, not vitamins. 

One of the principles Fadell sticks to when weighing product concepts is sticking to ideas that solve a real problem, as opposed to just making something incrementally better. How do you know the difference? Fadell says that if you communicate your idea to a small audience of friends and they share the same problem, that's when you know your idea can take off. "It's solving for pain," he says. Not vitamins, but pain killers." 

3. Design for simplicity and beauty. 

When Fadell was showing early versions of his smart thermostat to friends and colleagues, some people advised him to add additional functionalities besides adjusting the temperature up and down by turning a circular ring. "People were like, 'It has to have a touchscreen. Everything has a touchscreen,'" he says, adding that this would have compromised the simplicity and beauty of the device. The lesson? Don't incorporate unnecessary features just to add functionality. "I didn't want to do anything else but make it a beautiful ring," he says.