The One Simple Quote That Has Driven This Serial Entrepreneur to SucceedThe author of 'Think and Grow Rich' and the inventor of the infomercial have this strategy in common.

If you've ever read Napoleon Hill's famousThink and Grow Rich, then you're familiar with the concept of setting your "chief aim." As Hill explains it, your chief aim is your intention. It's where you want to go. It's what you want to build. It's who you want to be. He underscores the importance of planting it firmly in your mind -- going so far as to write down your chief aim, and then say it out loud every morning and every night until it manifests itself in your reality.

Obviously, reciting a bunch of words from a page isn't going to turn you into a multi-millionaire overnight. That's not its purpose. The reason Hill encourages aspirational individuals to write down their chief aim and to remind themselves of it daily is to provide clarity. Clarity paired with extremely focused work ethic is the true recipe for success.

Other successful people use variations of this approach

Other successful people use variations of this approach. Kevin Harrington is a serial entrepreneur and best known for inventing "the infomercial." He has sold billions in products and been a judge onShark Tank.In a recent interview, Harrington explained that he largely attributes his success to a simple quote which inspires him to take a positive approach to life.

"I have a saying that I live by, and it goes like this," he said. "'Whatever you visibly imagine, ardently desire, sincerely believe and, most of all, enthusiastically act upon, it must inevitably come to pass.'"

This is a quote originally from the late Paul J. Meyer, an author and global authority on goal setting, motivation, time management and personal and professional development.

“I visibly imagine myself being an entrepreneur"

"I visibly imagine myself being an entrepreneur -- and have been since I was 15 years old, sealing driveways for extra money," Harrington said. "I ardently desire being an entrepreneur. I sincerely believe I will be an entrepreneur. Now, a lot of people say those same things, but do you know where they fall down? They don't enthusiastically act upon becoming an entrepreneur, and that's what I did, every single day."

This speaks to a much bigger lesson about what it truly takes to manifest your reality and ultimately build whatever it is you want to build. It doesn't happen immediately -- nor should it. You first must face obstacles and learn lessons. You must embrace your challenge with persistence, focus, discipline and enthusiasm.

I want to continue approaching entrepreneurship with excitement

"I do 100 events a year," Harrington said. "And I know I don't need to do them, but I want to do them. I want to continue approaching entrepreneurship with excitement. I want to continue stretching my curiosity muscles. I want to continue improving, because that's what it's all about. It's about the process, and the love of the business."

Can I imagine my goal?

To adopt this mindset, the next time things aren't going your way, ask yourself: Can I imagine my goal?; Do I sincerely believe I can make it happen?; and, most of all, am I enthusiastically acting upon my ambitions every single day?

If you answer "yes" to all three, then be patient. Remember, "It must inevitably come to pass." If it worked for Harrington and Hill, maybe it will work for you, too.