For better or worse, cash is the oxygen of your business, and you can't last long in any environment without it.

There are two elements to nailing a job interview: form and substance. 'Form' describes the outer layer of your character - your manners, your demeanor, your social skills. 'Substance' describes the inner core of your character - your intellect, your empathy, your creativity.

Be personable to everyone you interact with.

Social enterprise is at its most impactful when the goal is empowerment, not relief.

Businesses should focus on solving problems, putting the customer first, delivering value - not gimmicks - and growing in a sustainable manner.

I was captain of the soccer and basketball teams in high school, and I was the equivalent of class president.

Warby Parker is a data-driven company.

My goal is to get in bed by 11. That rarely happens. But I celebrate when it does happen.

Young people entering the job market seek employment at companies with values that match theirs.

It's impossible to predict crises - or to control them once they hit - but you can absolutely prime yourself to ride them out as best as possible.

For many startups, ideating is the fun part: coming up with ingenious schemes to grab eyeballs and start conversations. But before you dive into that stage, take a step back and define your goals.

The trick to maximizing your team's productivity is to create a workspace that's flexible, so it can be altered according to the ever-changing needs of the company and its team members.

I came to Washington primarily to meet other entrepreneurs. That being said, I was also curious to hear how our federal government was thinking about entrepreneurship.

Creativity flows when curiosity is stoked.

A good collaboration pushes the boundaries of both partners.

It's not easy to keep good sleep habits as an entrepreneur, especially at the early stages when there's always a fire to put out.

Within an office, it's important to create opportunities for anonymous feedback.

The idea that you don't spam people with five emails a day or that you offer free shipping just seemed obvious to us, because that's how we want to be treated as consumers.

Just as a company needs a strategy to capture market share, a company needs a strategy to encourage actions that reflect their core values.

I personally try to buy the best-quality items at the best price that do the least harm and from companies that are striving to do good - many of those companies are run by young entrepreneurs.

It may seem premature, but you need to be thinking of your exit from the moment you accept capital, because at that moment, you've made an explicit agreement with an investor that he or she will eventually be able to gain liquidity.

Millennials are eager to make an impact, which makes them ideal for start-ups.

If you're entitled, you likely think you know more than you do.

Every day, write down a few frustrations. And then at the end of the week, you'll have maybe 10 problems. By the end of the month, maybe you have 40 to 50 problems. And then you can spend time thinking about, Is there a viable business in solving any of these everyday frustrations?

My grandfathers on both sides were entrepreneurs.

When my three co-founders and I started Warby Parker in 2010, our primary intention was to sell good-looking, affordable eyewear online.

For any collaboration to work, each partner must have a strong sense of identity. If one overpowers the other, it's like mixing lemonade with water - you wind up diluting the brew.

We all have a personal recipe for productivity. One person may need six cups of autonomy and just a pinch of collaboration. Another person may require heaps of sociability and noise, with just a teaspoon of occasional privacy.

All companies - and not just startups - face the same eternal challenge: resource allocation.

When you look at the reasons people leave companies, it's usually because their boss is a jerk or because they aren't learning and growing.

It's never easy asking for help.

On the day it launched, Warby Barker received more than twice as many visits as our regular site.

Every moment contains an opportunity to create feelings of satisfaction and excitement in a customer. It's up to retailers to make it happen.

The key to an ideal workplace, in one hyphenated word, is this: self-awareness.

When another editorial pops up denouncing millennials for some perceived generational flaw, I take it with a Miley Cyrus-sized grain of salt.

Walking in the morning improves my whole day. I think more clearly, my points of view are sharper, and I'm more decisive.

Exploring emerging technologies like new refraction technology will enable people to get prescriptions cheaper and more conveniently, which will, in turn, provide increased access to prescription glasses.

At Warby Parker, we use the survey platform Culture Amp to take employee engagement surveys that help us become ultra-responsive to the needs of our teams.

Creativity is a business imperative.

Share your personality with interviewers, but keep a professional filter safely adhered to it.

I wanted to open up a stand to sell dried fruit and beef jerky where we lived in Greenwich Village. I was 8 years old. I had been flipping through TV channels and got mesmerized by this infomercial for a food dehydrator.

I want to go at least 11 hours without food. I sat next to Hugh Jackman at a conference, and he told me he fasted 12 to 14 hours when he was training for the Wolverine movies. I've deluded myself into thinking I can effortlessly achieve the same body type as Hugh Jackman if I keep up this eating schedule.

We have been very focused on eyeglasses in particular because it's a massive industry.

Self-aware employees make a self-aware company.

If faced with two competitive candidates, every company will hire the person who evinces more enthusiasm.

Theoretically, an open-plan office is a great format for a changeable work environment, a place where employees have a say over how they work and a place that can adapt to their needs and to the needs of the business.

Giving employees agency over their workspace encourages them to think carefully about the conditions in which they work best, and it gives them the tools to forge that environment.

From the beginning, we believed that it was possible to develop direct relationships with customers at a relatively cheap cost, and our plan was to build a lifestyle brand that was also an Internet company - a rarity for eyewear.

Building a consistent experience and firm identity was instrumental in our ability to swiftly build our online presence, open four stores as well as a mobile store in a converted yellow school bus, and launch six shops-in-shops.

All those articles that scold Millennials for their supposed entitlement? Forget them. Millennials are great employees.