I don’t have an MBA. I failed economics. I’ve even had two of my businesses go under. However, I’ve never given up.

I went from being an ESL teacher to a time management consultant who works with individuals and corporations on increasing productivity and profits while reducing attrition and stress. It didn’t happen overnight, but for over a decade now I’ve dedicated myself to my craft. I picked up every book and audio program on business and personal development I could get my hands on (and had enough space for).

I love looking at the books that make up my own private library. Napoleon Hill, Tony Robbins, Jack Canfield, Jay Abraham, and John Maxwell are just a few of the names on my shelves. This week, I decided to revisit The Essential Drucker.

For every entrepreneur or executive, Drucker is a household name. His books are an absolute must-read for anyone serious about business. Rereading his book this week, what impressed me most was his insight into the changing world. He also had a deep understanding of the psychology behind productivity and human nature and saw both the incredible potential and dangerous effects the Internet would have on business.

Here are 11 lessons every entrepreneur should learn from Peter Drucker.

1. “What gets measured gets improved.”

Analytics is the name of the game. Without numbers, we can’t track our progress or growth. Numbers allow us to see where we stand. Numbers give us something to work from, to analyze, to see what is working, and what isn’t.

2. “People who don’t take risks generally make about two big mistakes a year. People who do take risks generally make about two big mistakes a year.”

Risk is a four-letter word. Many people fear risk, but to be successful in life, in business or even with the man/woman of our dreams, we have to be willing to take chances. Our goal should never be to eliminate risk but mitigate it.

3. “The manager who thinks that he can discuss the plans, directions, and performance of one of his subordinates in fifteen minutes – and many managers believe this – is just deceiving himself.”

Too many people underestimate just how long a single task will take and often overcommit themselves. This often leads to a highly stressful environment.

4. “Which of the activities on my time log could be done by somebody else just as well, if not better?”

To grow a company, delegation is critical. One person can only do so much. The goal of every entrepreneur should be to free up their plate as much as possible to allow them to focus on areas where they are most needed.

5. “If executives in an organization spend more than a fairly small part of their time in meetings, it is a sure sign of malorganization.”

Meetings are needed to keep things on course – that’s a given. However, too many organizations spend an inordinate amount of time in them. Many have meetings out of tradition rather than necessity, and, often, some people in attendance would be better off not attending in the first place.

6. “Effective people know that time is the limiting factor. The output limits of any process are set by the scarcest resource.”

The effective person understands the value of time. The ineffective person doesn’t. Employees spend on average eight hours at the office, but the results of each employee vary greatly. Effective people invest their time in learning skills and activities that get results.

7. “Managing the knowledge worker for productivity is the next great challenge for American management.”

With all the tools we have at our disposal today, you’d think every employee would be a productivity ninja. But very few are. For companies to maximize their team’s individual talents, time management and productivity are two things that more businesses need to offer training on.

8. “What is important is not the tools. It is the concepts behind them.”

Tools are just that, tools. As Jim Rohn, the late great American business philosopher once said, “You can cut down a tree with a hammer, but it takes about 30 days. If you trade the hammer for an axe, you can cut it down in about 30 minutes. The difference between 30 days and 30 minutes is skills.” A tool’s effectiveness depends on the person using them.

9. “Innovation is risky. But so is stepping into the car to drive to the supermarket for a loaf of bread. All economic activity is by definition “high risk.” And defending yesterday – that is, not innovating – is far more risky than making tomorrow.”

Excite. MySpace. Kodak. Blockbuster. There are many more multibillion-dollar companies that once dominated their market. The mistake many made has to be what I refer to as “resting on their laurels.” I’ve always been a huge fan of a concept made famous by 3M where employees are allowed to spend 15% on projects of their own choosing. Today, 3M has over 22,800 patents, does more than $20 billion in annual sales, and has a product line 50,000 deep. Innovation is a critical component of any business in today’s breakneck-speed, ever-changing world.

10. “For the first time in history, individuals can expect to outlive organizations. To manage oneself, therefore, will increasingly require preparing oneself for the second half of one’s life.”

The 20th-century business model was people would work to get into a good company, work their way up through the organization, and finally retire. Today, we need to take a bigger role in our career. In a world of mega-mergers such as AT&T and Time Warner, you can’t rely on always having your job.

11. “The twenty-first century will surely be one of continuing social, economic, and political turmoil and challenge, at least in its early decades.”

Drucker nailed it. Despite only being 18 years into the 21st century, we’ve had the housing bubble pop, migration concerns in Europe, and the rise of social justice warriors especially after Trump came into power. I think Drucker would agree with me when I say we’re still in choppy waters. Corporations and individuals will need to adapt to the changing winds if they are to succeed.Opinions expressed here by Contributors are their own.

Adrian Shepherd

Adrian Shepherd started his career as an ESL teacher in Japan, but today focuses on consulting with individuals and companies on productivity. His background in education helped him develop The One-Bite Time Management System (TMS), a revolutionary new system based entirely around simplicity: small bites that people can digest easily. He is also a contributor for the Huffington Post, Thrive Global and The Good Men Project. He is based in Osaka, Japan.