A famous art professor died and went to heaven. At the pearly gates, the professor asked St. Peter, “Sir, I spent most of my life on Earth studying great art, but I have a question that has puzzled me for 30 years: Who was the greatest painter in history?”

St. Peter pointed to a nearby cloud. “See that woman right over there? She’s the one.”

The professor frowned. “But I knew that woman on Earth! She ran the cafeteria at the university where I taught! How could she have been the greatest painter in history?”

St. Peter shook his head sadly. “She could have been, if she ever picked up a brush and tried to paint.”

I suspect that woman had been good at her job, but did she reach her real potential? Did she follow her passion? Was she content to let her dreams evaporate?

Those are tough questions to answer, especially when you consider that most of us find something we are reasonably good at where we can earn a living and leave it at that. But is that the legacy you want to leave?

What do you want to be when you grow up? Good news: There is rarely just one answer. I am of the opinion that we all have tremendous potential if only we allow ourselves the freedom to try. The problem starts when we box in our futures according to what we studied in school or family expectations or staying in a job that doesn’t challenge us to grow and flourish.

But you are ultimately responsible for your own success, in both your career and personal lives. What do you really hope to accomplish in your life? And do you have a plan for getting there?

It starts with figuring out your purpose in life. As lofty as that sounds, I assure you, it’s not rocket science. I’ve shared my story often: At a young age, I imagined myself owning a factory and being an entrepreneur. I had to fill in a lot of blanks along the way and learn some very difficult lessons, but in my heart I knew it was worth it.

Ask yourself some helpful questions. What excites you? What do you want to learn? What do you love to do? That last question is especially important, because as I like to say, find something you love to do and you’ll never work a day in your life.

Then develop your personal mission statement. In 25 words or less, define what makes you uniquely qualified to achieve your dream. Say it out loud every day to build your confidence and commitment.

Think about what you have already accomplished and what steps you need to take both short- and long-term. Do you need to learn new skills, line up funding, work with a business partner?

Are you building a network of contacts that can help and advise you as necessary? You need to connect with people in many fields and professions.

Define what success will look like. Will you recognize it when you achieve it? Are you prepared to change your definition as circumstances change?

The cafeteria worker may not have been able to give up her job and benefits to paint full time, but she could have pursued art as a hobby. Starting small is a practical way to test whether you can achieve your dream.

An Irish missionary shared this inspirational message in a London church:

“Consider the walnut: If you compare a walnut with some of the beautiful and exciting things which grow on our planet, it does not seem to be a marvelous creation. It is common, rough, not particularly attractive, and certainly not valuable in any monetary sense. Besides, it is small. Its growth is limited by the hard shell which surrounds it. The shell from which it never escapes during its lifetime.

“Of course, that’s the wrong way to judge a walnut. Break one open and look inside. See how the walnut has grown to fill every nook and cranny available to it? It had no say in the size or the shape of the shell but, given those limitations, it achieved its full potential of growth.

“How lucky we will be if, like the walnut, we are found to blossom and bloom in every crevice of the life that is given to us. Take heart. If one nut can do it, so can we all!”

Mackay’s Moral: The only person who can limit your potential is you.

A farmer famed for his agricultural knowhow once hired a neighbor's teenage son to help him do the spring plowing. The farmer believed in letting people do their work without undue supervision, so he placed the boy on the tractor and went over the hill to work on another field. Anxious to plow straight furrows, the inexperienced teenager kept looking over his shoulder to check how he was doing.

Despite this precaution, he was dismayed to find that by the time he reached the edge of the field, the row he was plowing was noticeably crooked. He tried and tried, but he was unable to keep the rows straight.

When the farmer came back to see how the young man was doing, he instantly saw what was the problem. Taking the boy aside, the farmer told him in a calm voice, “You can't plow a straight row if you continually look back. You must keep your eyes focused straight ahead. And always remember where you've been.”

So it is with a lot of important tasks in life -- don’t just look back; instead focus on the future. Our eyes are in front of our heads because it is more important to look ahead than to look behind.

Satchel Paige, one of the greatest baseball pitchers of all time, was asked by a writer for Collier’s magazine about his philosophy of life since he seemed ageless. One of them was “Don’t look back. Something might be gaining on you.”

I don’t know of a single company that doesn’t hope to be in business beyond the end of the day. That’s why planning and goal-setting are such important activities. An organization that doesn’t take those jobs seriously has already doomed its own future.

Whether you hope to start your own business, aspire to advance in the organization you currently work for, or just want to support your employer’s success the best you can, understanding how a business grows and survives is a critical skill. These factors influence your fortunes and your organization’s growth over the long haul. Pay close attention to them.

Trust -- Whatever your role, concentrate on keeping your word and living up to your values. Customers and co-workers want to know they can depend on you. Management takes notice of and values trustworthiness above just about every other trait. You also need to be aware of your organization’s trustworthiness as perceived by customers and vendors.

Decisiveness -- Learn to make decisions promptly instead of waiting for every last piece of data. An imperfect decision that you can correct later is usually preferable to a right answer that comes too late. Every decision you make could potentially affect your organization’s future.

Competition -- Study your market and get to know everything you can about other players in your industry. You don’t want to be caught off guard by a rival’s new idea, and you don’t want to always be on the defensive against what the competition is up to.

Records -- Be meticulous in documenting your activities. Good records help you preserve ideas, establish your credibility, and prove your point when the facts aren’t clear. This applies to finances, employees, ideas and everything else you and your organization are responsible for.

Network -- Build relationships and connections with a wide variety of people in and out of your industry. Your network can be a source of ideas, employees and advice, but it can take time to build up. Take advantage of any opportunity to meet new people who can help you and whom you can assist in return. As I like to say, “Dig your well before you’re thirsty.” The time to establish a network is before you need it. And in the future, you will in all likelihood need to turn to your network for a variety of issues.

Patience -- Concentrate on incremental progress, not blockbuster victories. Establishing a habit of slow but steady success will build everyone’s confidence and minimize risk. Overnight successes almost never happen overnight; they are usually the result of months or years of hard work.

Learning from the past is perhaps the best way to prepare for the future. Always remember where you’ve been.

Baseball “philosopher” Yogi Berra offered a memorable observation about the nature of the future. Having witnessed the extraordinary progress of a rookie just breaking into the major leagues, Yogi remarked: “His future is ahead of him.”

Mackay’s Moral: The person who does not look ahead remains behind.

American mathematician Norbert Wiener had a reputation for being a little absent-minded. According to one story, when his family moved to a new Massachusetts home, his wife insisted on supervising every detail of the move because she couldn’t depend on Wiener to remember the important details -- like their new address.

Wiener went to work on the day of the move with a piece of paper his wife had given him; on it was written his new address. During the course of the day, he used the paper to work out an equation and then discarded it. At the end of the day, Wiener returned home to his old address, now an empty house.

At the door, he suddenly remembered that his family had moved, but he had no idea where his new home was. Spotting a little girl riding her bike down the street, he called out, “Excuse me, I’m Professor Norbert Wiener, and I’ve just moved. Would you by any chance know what my new address is?”

The young girl replied, “Hi, Daddy! Mom said you’d forget.”

The good news is that, even if your memory is better than Professor Wiener's, it can still be improved. There are many ways that you can train yourself to have a better memory.

Like every other skill, it takes practice and a commitment to get better. Many of my friends think my memory is terrific, but they don’t know my tricks. Like most people, I forget 50 percent of what I hear within hours, so I make a point of writing things down.

I also have a special phone dictation line at my office. I can call it 24 hours a day, seven days a week and leave all sorts of messages, letters, notes and so on. And I don’t go anywhere without my iPhone, paper and pen. I am constantly writing myself notes and leaving them where I can find them. I’ve been known to put notes on my steering wheel and dash in my car, on my office chair and phone at work. I put them on the floor by my bed so I see them when I wake up in the morning, on my bathroom mirror or in my sink.

Name association is another arrow in my quiver. When I meet someone and want to remember their name, I associate names of other famous people with the same names and repeat them over and over to myself. Similarly, to help me with phone numbers, I think about how I can connect the number to a significant date or event. Repetition aids retention. I repeat things over and over, which helps me remember names, phone numbers and key statistics. Also, I’ve learned that if I write things down enough, I will remember them.

A study by UCLA researchers found that older people can improve their brain function after just 14 days of following some simple, healthy lifestyle strategies. Incorporating healthful food, physical activity, stress reduction and memory exercises seems to help improve cognitive function.

Here are some of the health strategies participants worked into their daily routines:

-- Memory exercises, such as crossword puzzles and brain teasers were worked on throughout the day.

-- Five small meals a day in order to prevent drops in blood glucose levels, because glucose is the main source of energy for the brain. Participants also ate diets rich in omega-3 fats, antioxidants and low glycemic carbohydrates like whole grains.

-- Daily relaxation exercises to prevent the release of cortisol, a hormone that can impair memory and damage memory cells.

-- Daily walks.

Up until about 10-15 years ago, it was believed that we were born with a fixed number of brain cells that eventually died out. Now scientists know that brain cells regenerate throughout our lives. And one thing seems clear: To keep the sharpest memory you can for as long as you can, get moving. Aerobically, that is. Studies have shown that people who engage in aerobic exercise perform better cognitively and show increased brain volume. In another study, participants who exercised showed lower rates of dementia. That’s because exercise actually encourages neuron generation in the part of the brain that processes memories.

Back to the absent-minded professor. Wiener once observed to a colleague, “People attach much too much importance to memory.”

“I disagree,” said his colleague.

“Disagree with what?” asked the professor.

Mackay’s Moral: Pale ink is better than the most retentive memory.