What do entrepreneurs need more than anything else? Brain fuel. The creative brain is one that is constantly fed.

So why not learn from giants of entrepreneurial thinking. Consider re-writing one of these 10 powerful quotes and posting it in an obvious place for a couple of days. Stand on the shoulders of the really big thinkers and enjoy the elevated view.

1. Harvey Mackay, author.

“Positive thinking is more than just a tagline. It changes the way we behave. And I firmly believe that when I am positive, it not only makes me better, but it also makes those around me better.”

Many people have downplayed or disparaged popular psychology, but Mackay has it right. Your positivity in infectious and beneficial.

2. Peter Drucker, “The Effective Executive.”

“Meetings are, by definition, a concession to deficient organizations. For one either meets or one works. One cannot do both at the same time.”

Zing. Sales professionals: do whatever it takes to get out of non-productive meetings. You can meet or you can sell, but you can’t do both at the same time.

Related: 50 Inspirational Quotes to Motivate You

3. Jim Loehr, “The Power of Full Engagement.”

“Expose the muscle to ordinary demand and it won’t grow.”

I apply this to that one particular muscle we call the brain. Stretch the brain. Feed it regularly. Challenge it. And watch it grow.

4. Daniel Kahneman, “Thinking Fast and Slow.”

“People judge competence by combining the two dimensions of strength and trustworthiness.”

Want to be a great influencer? Show strength by being the go-to resource for your client. Show trustworthiness by doing what you say you’re going to do.

5. Stephen R. Covey.

“Most people do not listen with the intent to understand; they listen with the intent to reply.”

Ouch. Guilty as charged, Mr. Covey. I know what it is like to take part in a conversation where I am only but waiting for the speaker to take a breath so I can dazzle that person with my brilliance. This quote convicted me from the first time I read the book.

Related: Inspirational Quotes From 100 Famous Business Leaders (Infographic)

6. Marie Curie.

“I was taught that the way of progress is neither swift nor easy.”

Want to get better? A price must be paid. Good news: the payoff is worth it.

7. Theodore Roosevelt.

“Courage is not having the strength to go on; it is going on when don’t have the strength.”

We all know this battle. A voice in your head says, “It’s okay — hang it up — you’re tired — shut it down.” It’s that smaller voice that we must heed, the one that says, “Everyone else is shutting it down — this is your time to be great.”

8. Martin Luther King.

“Everybody can be great, because anybody can serve. You don’t have to have a college degree to serve. You don’t have make your subject and verb agree to serve. You only need a heart full of grace. A soul generated by love.”

I love this quote because it speaks of a leveling of the playing field. Serve first — everything else will fall into place.

9. Anonymous.

“You are free to make choices, but you are not free to escape the consequences.”

This saying works both ways. Great choices in your daily plans bring great consequences; poor choices… well, you know. This is a great life philosophy. Teach it to your kids.

Related: 10 Inspirational Robin Williams Quotes

10. E.E. Cummings.

“Always the beautiful answer who asks a more beautiful question.”

I doubt that cummings (he refused to capitalize anything except the word “God”) was talking about entrepreneurs when he wrote this, but these are words to live by. Want to get beautiful answers from your customers and from your team? Start focusing on more beautiful questions.