Great quotes help motivate me to keep learning on my journey of self-improvement. One of my favorite sources of quotes to turn to is from self-made billionaires, as they have spent their lives working through failure, and have come out on top. They often have wisdom to impart.

For those days when you need an extra pick-me-up, here are the best motivational quotes from some of the greatest entrepreneurs in history.

1. "People who are unable to motivate themselves must be content with mediocrity, no matter how impressive their other talents." -- Andrew Carnegie

2. "The way to get started is to quit talking and begin doing." -- Walt Disney

3. "It is our choices that show what we truly are, far more than our abilities." -- J. K. Rowling

4. "Obstacles are those frightful things you see when you take your eyes off your goal." -- Henry Ford

5. "You don't learn to walk by following rules. You learn by doing and falling over." -- Richard Branson

6. "When you grow up, you tend to get told that the world is the way it is and your life is just to live your life inside the world, try not to bash into the walls too much, try to have a nice family, have fun, save a little money. That's a very limited life. Life can be much broader once you discover one simple fact, and that is that everything around you that you call life was made up by people that were no smarter than you. And you can change it, you can influence it, you can build your own things that other people can use. Once you learn that, you'll never be the same again." -- Steve Jobs

7. "You can do so much in 10 minutes time. Ten minutes, once gone, are gone for good. Divide your life into 10-minute units and sacrifice as few of them as possible in meaningless activity." -- Ingvar Kamprad

8. "The big secret in life is that there is no big secret. Whatever your goal, you can get there if you're willing to work." -- Oprah Winfrey

9. "I knew that if I failed I wouldn't regret that, but I knew the one thing I might regret is not trying." -- Jeff Bezos

10. "If something is important enough, even if the odds are against you, you should still do it." -- Elon Musk

11. "The biggest risk is not taking any risk... In a world that's changing really quickly, the only strategy that is guaranteed to fail is not taking risks." -- Mark Zuckerberg

12. "Don't be afraid to give up the good to go for the great." -- John D. Rockefeller

13. "Success is often achieved by those who don't know that failure is inevitable." -- Coco Chanel

14. "You can learn from everybody." -- Sam Walton

15. "When I saw that screen light up that day in the Merrill Lynch offices, I lost any residual doubt that Bloomberg could make it. We had picked just the right project. It was big enough to be useful, small enough to be possible. Start with a small piece, fulfill one goal at a time, on time. Do it with all things in life. Sit down and learn to read one-syllable words. If you try to read Chaucer in elementary school, you'll never accomplish anything. You can't jump to the end game right away, in computers, politics, love, or any other aspect of life." -- Mike Bloomberg

16. "You can't build a reputation on what you are going to do." -- Henry Ford

17. "All my life people have said that I wasn't going to make it... You can never quit. Winners never quit, and quitters never win." -- Ted Turner

18. "Your time is limited, so don't waste it living someone else's life. Don't be trapped by dogma -- which is living with the results of other people's thinking. Don't let the noise of other's opinions drown out your own inner voice. And most important, have the courage to follow your heart and intuition." -- Steve Jobs

19. "Making mistakes is the privilege of the active -- of those who can correct their mistakes and put them right." -- Ingvar Kamprad

20. "Risk more than others think safe. Dream more than others think practical. Expect more than others think possible. Care more than others think wise." -- Howard Schultz

21. "High expectations are the key to everything." -- Sam Walton

22. "I'm always afraid of failing. It's great motivation to work harder." -- Mark Cuban

23. "Go as far as you can see; when you get there, you'll be able to see farther." -- J.P. Morgan

24. "What I know for sure is that if you want to have success, you can't make success your goal. The key is not to worry about being successful, but to instead work toward being significant – and the success will naturally follow." -- Oprah Winfrey

25. "Whether you think you can or you think you can't, you're right." -- Henry Ford

Foolish takeaway
Life is a journey, not a sprint. Those who succeed spend their lives continuously learning habits, skills, and practices to effectively reach their goals, and live a successful life. Learning how to successfully invest for the long term is one of the best educations anyone could ever give you.

Dan Dzombak can be found on Twitter @DanDzombak, on his Facebook page DanDzombak, or on his blog where he writes about investing, happiness, life, and success.Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.