Back when I was in college (for the short amount of time I attended), there was no major for entrepreneurship. In fact, I would argue it's something you can't fully learn in school, no matter how diligent the curriculum. There's no class that walks you through how to stomach the ups and downs of the journey. 

I never finished college, but I went on to become a successful entrepreneur. It's a story I tell in full in my book, All In: 101 Real Life Business Lessons for Emerging Entrepreneurs, but the shortened version is that in 1977 I was just a kid that had started a flea market business, with my dad as my business partner. My senior year of high school, we bought a hardware store to expand our business, and I told my dad I wanted to give college a shot.

One day, I was in my Introduction to Business Management class, and the teacher stopped me and said, "You come to school in a suit?"

I explained, "I have a business with my dad. After class, I leave school to go sell to clients."

My teacher asked if I would speak to his sales class. I said sure.

What I learned shortly after was that my teacher had never run a business much bigger than a little storefront on the Ocean City boardwalk in New Jersey. And here I was, working like a dog just to pay for these classes--which took little more than nothing to pass. I felt like school wasn't going to teach me what I actually wanted to learn, so I left.

Now, I'm not saying to not get your education. Part of me regrets not finishing college for the experience of it all. But I do consider college to be a bit of a double-edged sword. Anyone who knows my story and the businesses I have built knows that I've reached success in many different industries. I've also had a few failures along the way as well. I don't claim to be some know-it-all with a silver-bullet business solution that's going to turn your goose gold and send your company to the top of the NASDAQ overnight. 

Newsflash: that guy with the silver bullet doesn't exist.

What has allowed me to become a successful entrepreneur, however, is the fact that I'm just a curious, determined person who knows how to adapt to the changing times and compensate for my shortcomings. I learned all I know on the street, talking to clients, knocking on doors, and pounding the pavement.

You don't need an MBA to do what I do. In fact, you don't even need to spend any money to learn these lessons. 

1. Always be on time. No matter what.

This may sound like a no-brainer, but if you want to achieve any serious goal in life--always be on time. It's part of being a professional, and it's an easy thing to make part of your routine. It shows your customers and business partners that you have integrity. It shows that you can be trusted. It shows that you care and respect their time, and that when you say you're going to do something, you mean it.

2. Be positive and smile.

Who wants to be around unhappy people? No one wants to work with people who have bad attitudes. 

Be nice to everybody, and I mean everybody, all the time. You'll be amazed how important "gatekeepers" like receptionists and assistants are to your success. You saw the move Wall Street, right? How did Bud Fox get in to see Gordon Gekko? He buttered up his secretary. Be like Bud. Be nice to everyone. 

3. Return calls in less than 24 hours.

When I was building my first company, Wilmar Industries, it drove me crazy to hear customers complain that they hadn't gotten a call back for three days. Wilmar may have become a massive company, but I was a mom & pop entrepreneur at heart. I felt (and still feel today) like every single person you do business with matters. It doesn't matter if it's a customer or a big-wig investor. 

I constantly told all my employees, "No one wants to feel like they have been left blowing in the wind. If you want their business, you better be responsive. Call everyone back within twenty-four hours, no matter what."

I was so passionate about this, I had a personal 800 number installed in my office just for customers. If I was in my office and the phone rang, I'd pick up and say, "Bill Green speaking, what can I help you with?" It was no publicity stunt, the CEO answering calls directly. I sincerely wanted to help any customer at any time.

4. Find a mentor.

Looking back, I can pinpoint all the different mentors at each fork and pivot on the road that helped me move past whatever obstacle I was facing at the time.

Mentors are valuable teachers, and often times become close friends. They are knowledgable, patient, and willing to teach--under the assumption that you are willing to listen, learn, and take what they say and run with it.

Nobody becomes successful alone. Even the world's most accomplished entrepreneurs, CEOs, and business leaders today have mentors. We're all learning from each other.

5. Look successful, act successful, be successful.

People want to do business with successful people. So guess what? You have to look and act like you belong in the room to win people's business. You have to believe in yourself before anyone else will. 

Some people call this "faking it until you make it," but you can't fake it. You have to put yourself in the mindset that you believe in everything you're doing and everything you're going to deliver on. It's all about having a positive attitude and making your intentions clear to the world. You may not be the most sharply dressed person out there, but you have got to make an effort to do your best with what you have. I'm not saying you have to drive an expensive car. But you need to drive one that's clean and presentable, if you want to be taken seriously.

6. Sweat everything.

Remember the book, "Don't Sweat the Small Stuff" that came out in the nineties? I read it and took it to heart when it came to my personal life. Who cares if your spouse doesn't put the cap on the toothpaste or if your kid keeps spilling milk at the dinner table? Life is too short to be that much of a stickler.

But let me tell you, I hate that book when it comes to doing business. You've got to sweat the big stuff, the small stuff--you've got to sweat everything.

It all matters. Especially when you're running your own company.

7. Winging it is not a strategy.

And finally, when it comes to succeeding in business, here's one sentence you never want to hear, or say yourself: "It'll work out."

Really? How do you know? Business isn't always predictable. You can't just sit back and wait for life to happen because when you do, unexpected stuff usually happens. You have to be smart. You have to be prepared. You have to walk in to every situation with a well-devised plan of attack.

I can't stress this enough. When starting your own business, "winging it" is not an option.

Do your homework, and know everything you can about everything you can think of that's relevant. The more you know about a customer, a product, a market, or even an employee, the greater advantage you have. And I'm not just talking about business and sales.

I'm talking about everything you do in this world.