When I was student at MIT, I learned an important lesson from one of my personal heroes, Amy Smith. She's a hero because she invented the "screenless hammer mill" when farmers in Senegal were struggling with the process of separating rocks from grains when making flour. Expensive screens broke all too easily and were hard to replace in poor remote rural villages. Her invention, which was recognized by the Lemelson-MIT Student Prize, looked at the existing problem at a new angle. Instead of screens, she used airflow to separate unground grain and rocks from flour. By applying simple aerodynamics, she eliminated the need for screens altogether, and increased grinding rates by 60 times.

This story has served me well in my start-up career. Whenever I get stuck on a problem, all I need to do is stop fixating on my current solution and redefine the problem instead. Smith looked at the problem from a different perspective, which lead to a solution outside of the box. Similar stories can be distilled into useful pieces of advice that have also helped me along the way:

1. Accept the fact that you are inherently lucky. There is a story about a research experiment that involved two types of subjects. One group self-declared themselves as unlucky; the other believed that they were very lucky in life. Both were given newspapers, and were asked to count the number of pictures from cover to cover.

While the unlucky group took on average two minutes to flip every page and count the total number of pictures on the newspaper: 27. The lucky group noticed on the second page a large note saying "Stop reading here, there are 27 pictures on this newspaper." So they stopped and reported the number within 10 seconds of being assigned the task. So many times we fall into the trap of focusing too narrowly on our daily targets that we miss the opportunity to notice the more creative answers right in front of us. The luckiest people are constantly stimulating the brain with a certain level of randomness through serendipitous encounters, conversations and insights. They are able to focus on a target without shutting down their ability to see beyond that target. They can turn their "blinkers," which block peripheral visibility in horses, into "visors," which give selective views--while still allowing the horse to focus on the race.

2. Don't take advice from golfers if you want to play baseball. Jeff Hoffman, a member of the founding team of Priceline and the most amazing storyteller, makes a point that's invaluable for start-up founders. Sometimes, we think that all smart people are able to provide great advice--and this may be true, to a certain extent. But the real truth is that if you wanted to become a professional baseball player, you wouldn't seek advice from a golfer. Yes, the swings might present similarities, and you might even be using some of the same muscles. However, I doubt the Tiger Woods of the golf world would seek putting advice from the Willie Mays of the baseball community. This is a good thing to remember when we choose our investors and assign Board seats.

3. Your personal happiness is worth working for, professionally. There is so much content out there about the "how" of entrepreneurship, but we sometimes forget about the "why" of this particular career choice. My favorite writer is Jorge Borges; despite all his literary accomplishments, his deathbed regret was that he did not manage to find happiness in life. I think of this often when I have one of those excruciating "bad start-up days" (a much more unpleasant experience, and yet as unpredictable as "bad hair days").

Some days, I genuinely wonder why I put myself through this torture, and then I tell myself that in order to be happy, my road to self-actualization involves creating legacy, and the path to impact is tortuous. The truth is that unhappy people are less creative, productive and more likely to be unlucky. I frequently ask people to share with me the first image that comes to mind when I say "happy moment." This could be reading a book in a coffee shop, a good conversation with a close friend or a challenging run at the gym. I then ask the question: "How many times per week do you have happy moments?" I am shocked to hear that more often than not, people tell me they can't remember the last time they had one of those! I believe--and Chip Conley and Tony Hsieh would concur--that successful start-ups have happy people, which is a requirement for happy customers and happy investors. Creating a start-up culture in which happiness is a core value is very important. What's the worst that could happen, anyway? You might fail to launch a product, but you will still walk away with happiness--it's not so scary after all.

Rebeca Hwang is a co-founder and CEO of the San Francisco-based start-up, YouNoodle, which gamifies innovation through competitions. She is a board member for Cleantech Open, Imagine H2O, and Bases. She was recently named one of the World Economic Forum's Young Global Leaders.