Design for yourself
A lot of business advice will tell you to focus on the customer. I think that's misguided. The best way to design anything is to design it for yourself.
When you ask yourself, what product would I really love to use, you get access to another level of insight and wisdom. It's subtler. It opens up to new inspiration, new ideas, to creativity. Instead of asking other people, ask yourself. You will be able to come up with ideas that wouldn't surface from your customers in a million years. Apple didn't ask people what kind of phone they wanted, because people wouldn't have known. They asked themselves, what kind of phone they wanted.
That's how you get to the genius.
It also requires that you take responsibility for it. You can't leave it to a committee. You can't say "well, it is this way because our customers wanted it this way". If something's off, it's your responsibility. That also means, it's something you can fix.