What 15 Entrepreneurs Learned From Their First Summer Jobs From retail to yard work and babysitting, these entrepreneurs share invaluable lessons they learned while working at their first summer job.

There comes a time in everyone's life when those long summer days at the pool morph into long days spent working and saving up money.

Though summer jobs aren't always ideal, or fun, they can help develop a solid work ethic, create good habits and build strong principles -- all of which can be extremely beneficial for entrepreneurs.

Taking a trip down memory lane, these entrepreneurs share the story of their first job and what they learned from the experience:

1. Generosity and gratitude go a long way.

Name: Heather Nichols

Company: Health, wellness and fitness consultant at Heather Nichols

Lesson: When I was 16, I got my first summer job at a high-end baby furniture store. After I had completed a week of training, they told me I would not be paid. I quit immediately and started working at a brand new art gallery for a woman who loved her business, loved what she did and valued me as an employee. She was happy to pay me, and there was an atmosphere of gratitude and generosity in her business. I learned the valuable lesson that generosity and gratitude for your employees goes a very long way in business, including the bottom line.

2. Work-culture matters.

Name: Evan Hackel

Company: CEO of Tortal Training

Lesson: My first summer job was raking leaves in a cemetery. The other workers never worked at all -- unless someone was watching. I had tremendous peer pressure not to work. The experience taught me how important culture is to creating an atmosphere of effective work and to inspect what you expect.

3. Think long term.

Name: John Demartini

Company: Founder of Demartini Institute

Lesson: When I was 9, I asked my dad if I could do something around the house to earn some money so I could buy a new baseball, bat and glove. He asked me if I had mowed the yard, edged the sidewalk, cleaned out the gutters, weeded the flowerbeds, trimmed the hedges, swept the driveway, cleaned out the garage and my room and shined his shoes. I told him that I had. He had nothing else for me to do and that he could not just give me money without providing a fair exchange of service, so if I wanted to earn some money I would be wise to go to the neighbours to see if they needed some form of work or service done.

My dad saw me a few days later with my new glove, ball and bat and asked me what I did to acquire them. I told him that I did all of the neighbourhood services. He asked me what equipment I used and I told him the equipment in the garage. He told me about depreciation and that I owed him $7.50 for using his equipment.

I was a bit discouraged. To remedy the issue, I hired three friends to help me with the yards and paid them a small percentage for their efforts. The neighbours spread the news of my services and I added six more friends and rented out two other sets of equipment from two other neighbours at the same rental rates as my dad had offered. I netted after all costs, salaries, gas, $45.00 a day back in 1963. My dad noticed that I kept spending all of my money and bought me a coin collection set and a large piggy bank to encourage me to think longer term and save my money rather than immediately spend it. My Dad told me that he wanted me to be a free independent young man so he started charging me for room, board and clothes a cost of $7.50 a month, but in turn he gave me my freedom to go anywhere I wanted to on my new bike as long as I was home by 9 p.m.

I still have the original piggy bank today. My dad never gave me the combination or the key to open it. It has the original coins from 1963 and before.

4. Be yourself.

Name: Chutisa Bowman

Company: Founder of BeFrabjous

Lesson: I was 17 at the time. I was an in-house fashion model for a well-known Australian women's fashion label, and I had an amazing time. Dressing up in a beautiful clothes, working closely with the designer and sales reps were the main requirements of the job, but these were not the only factors for doing a good job. I also had to develop a professional attitude and the ability to get on with a wide range of people. I learned to break out of my shell, to radiate confidence and assertiveness, to be more flexible with a positive attitude and to communicate effectively with all sorts of people in a fast-paced environment.

5. Work harder not smarter.

Name: Daniel Young

Company: Co-founder of B Invested

Lesson: When I was in college, I wanted to make some extra money and stay fit. I got a job delivering cases of beer to pubs around Sydney. It was back-breaking work. One thing it did teach me was the old saying, "work smarter not harder."

6. Never take no for an answer.

Name: Lauren Polly

Company: Author, speaker and life coach

Lesson: I was 11 when I took my first steps as an entrepreneur. I loved children and was eager to start my own babysitting business but my young age was preventing me from getting jobs. I saw a sign advertising child care classes for babysitters at the local recreation center and knew this was my ticket in.

I completed the course, along with my CPR certification. Since I was too young to be left alone with the children, I marketed myself as a "mother's helper." I had a booming business that summer helping multiple families, making money and having fun along the way.

Every time I hear the words "no' "you can't' "you're not qualified' I think of this early experience. I could have easily put off my dream of having a child care business until I was older but I found ways around it. I educated myself and marketed my business in a way that worked for me and my prospective clients.

7. Know your stuff.

Name: Tom Harari

Company: CEO and co-founder of Cleanly

Lesson: At age 14, my first summer job was working in the warehouse of a hip-hop clothing retailer. I went every day into that hot warehouse and loaded and unloaded shipments of apparel that were to be sold at one of their 35 stores. And every day, the CEO of the company would walk around talking to the staff, help them unload trucks and in general knew what was happening at all times. I learned a tremendous amount about the importance of knowing everything that goes on within your organization top to bottom.

8. Relax.

Name: Elliot Tomaeno

Company: Founder of ASTRSK

Lesson: I used to be a door greeter at a Cold Stone Creamery. My whole job was to entertain people while they were waiting for their ice cream. I had a blow-up guitar and a purple clown wig. This job taught me a lot about humility and how to have fun with myself — and, most of all, not to take myself too seriously.

9. Gain experience.

Name: Andrew Song

Company: Director of marketing and co-founder of Magic Instruments

Lesson: My first summer job was teaching kids how to swim at the local pool. While that's not anything significant in itself, it did give me first exposure to customer service, sales and the ability to earn a person's trust very quickly.

10. Be patient.

Name: Trisha Gregory

Company: Co-founder and CEO of Armarium

Lesson: My first job was during the summer while I was in high school. I worked as a beach waitress on St. Thomas. Not only was it fun, but it taught me incredible multi-tasking skills, the value of patience with others under stress, and inspired me on an entrepreneurial level.

11. Pay attention to the details.

Name: James Rohrbach

Company: CEO of Fluent City

Lesson: I was a salesman at a golf shop where we mainly sold attire, like polo shirts and shorts. This job taught me two big lessons. First, sales is hard. This was my first time ever trying to sell, and it was much more difficult and unnatural than I had anticipated. Second, details matter, and you have to constantly be working at it. I spent many hours a day folding and refolding shirts that customers had picked up, tried on or even just fussed with on the tables. It was never-ending, but if you didn't do it, the whole store looked terrible. I have carried both lessons with me to this day.

12. Everything in life is about sales.

Name: Magnus Larsson

Company: CEO and CPO of Rebtel

Lesson: My grandfather gave me my first summer job. He picked me up, and we went to his garage to fill up a large box with random stuff. We then drove to the flea market and bought a spot to sell the things. During these days, he taught me how to sell, negotiate, bargain and price things. It was probably the best school I had. My grandfather's only comment was: Everything in life is about sales! He was right.

13. Engagement is key.

Name: Healey Cypher

Company: CEO and co-founder of Oak Labs

Lesson: I worked as a cashier on the men's floor at a clothing retailer in Lincoln, Nebraska. my first summer in high school. Everyone should do it at least once. If nothing else, you learn the art of pleasantries, the importance of earnest engagement and perhaps most fundamentally that everyone just wants to feel important.

14. Lead with respect and appreciation.

Name: Zac Maurais

Company: Co-founder of Favor

Lesson: Senior year of high school I landed a summer internship at an ad agency. As the intern, the daily coffee run was just part of the job. My boss sent me out with clear instructions, "black with sugar." I returned to the office with the goods, but the response was not what I was expecting. He took a sip and exclaimed, "That's not what I asked for!? How the hell are you going to be successful here if you can't even get my coffee order correct?"

In that moment I promised I would never be that boss. Today I manage a talented team and do my best to treat people with respect and appreciation.

15. Customer service is paramount.

Name: Emily Motayed

Company: Co-founder and CMO of Havenly

Lesson: A standard summer job for me was actually hostessing at a restaurant in high school. The job really taught me a lot about sales techniques and skills, how to upsell customers, as well as negotiating power-- especially when converting upset customers to happy ones in a short period of time. These have all been invaluable skills that I currently use to this day as a co-founder.