One thing I've learned about success in business is that there is no single path to the top. Today's most successful company founders, entrepreneurs, and businesspeople got there in an almost infinite variety of different ways.

Mark McDonald left college at 19, and Josiah Humphrey left high school at 17, to pursue their dream of starting a business together. Says Josiah, "The reason why we did this was because we both had the belief and commitment that spending time working directly towards our dream, rather than spending the next four to five years in college, would set us up for success in the long run."

And they were right.

In August 2011, when the two friends were just 18 and 19 years old, they started their venture with a nest egg of less than $3,000. They rented an expensive office in the tallest building in the Southern Hemisphere, and that's where their new app development company-Appster-was born.

Four years later, the company employs more than 300 people, spread over three continents, with an 8-figure revenue. Appster will likely double in size during the course of 2016, and the company is on track to do $100 million in revenue by 2018. The founders are particularly proud to have never taken any outside funding-to this day they are completely bootstrapped.

While they don't recommend that everyone drop out of school to pursue their dreams of success, Mark and Josiah learned 5 priceless lessons along the way.

1. Follow your dream

Never be afraid to follow your dream. Understand that the route you take to get to your dream may not involve attending a college or university. People, teachers, your parents, and others will tell you that you are crazy and that you should follow the usual path through life. However, you don't need an MBA to startup and run a successful business-a lot can be learnt from doing-and you can't learn everything there is to know about running a successful company just by reading a textbook.

2. Be okay with being uncomfortable

Leaving school at a young age to follow your dream is by definition going way outside of most anyone's comfort zone. Understand you are not going to get anywhere in life by playing it safe. Sometimes you are going to be as scared as hell. This is a good thing, because it means you're growing. You should always check to see if you're comfortable because most of the time you won't notice. If you find that you've settled into a comfortable routine, figure out what goal/actions will make you uncomfortable again-and then pursue them.

3. Work your ass off

Hard work beats talent every day of the week, and if you can combine the two that's even better. Says Josiah, "I like to think of it this way; if someone works a standard 40-hour week, and I work 100 hours a week, I can theoretically do 2.5 years of work versus their 1 year of work. What might take someone 10 years to do, could be done by me in 4 years or less with the right focus."

4. Create your own curriculum

Although Mark and Josiah dropped out of school, they never stopped learning. In fact, they would tell you that they spend more time learning than most university students. The difference is that, as entrepreneurs, Mark and Josiah were able to create their own, tailored curriculum about the things that they interested in and could apply in a practical way to their business. Both make a point of reading books and keeping up to date with what's happening in the technology industry from the many publications they follow.

5. Vision

Appster's vision is to "Build a Development Hub for the Greatest Ideas and Innovations in the World." Mark and Josiah had this vision and were stating it to the world in the company's earliest days. Four years later, this vision drives every decision the company founders make, and it is instrumental in attracting great people to work for the business-and earning their ongoing loyalty and engagement.