'Shark Tank's' Lori Greiner on the Do's and Don'ts of Pitching The Queen of QVC explains what you should and shouldn't do during your next pitch meeting.

Lori Greiner knows how to sell an idea. Nicknamed "The Queen of QVC," she has made a small fortune convincing TV shoppers to buy her numerous inventions, including the Scrub Daddy and the Simply Fit Board.

As a judge on ABC's Shark Tank, she's known for having a sharp eye and quickly discerning a "hero" from a "zero." Her killer instincts have led her to invest in companies that have collectively earned more than $400 million.

Related: 5 Ways to Win Your Pitch, According to 'Shark Tank's' Robert Herjavec

Part of what makes Greiner so savvy is that she's been there and done that. When she watches a nervous entrepreneur make a pitch on the show, she can empathize because she was once in their shoes. Whether hawking her wares on TV or in a boardroom, she's learned over the years which approaches work and which fall flat. And she hasn't thrown in the towel in the face of rejection.

"Everything is a lesson," she tells Entrepreneur. "You're constantly learning, growing and improving as you experience different things."

Here she shares some valuable pitching do's and don'ts.

Be patient.

"Trust your instincts and wait for the perfect place and time to launch."

Related: The Best Investment the 'Shark Tank' Judges Ever Made for Under $100

Don't "rush a product launch or advance a marketing plan if your gut is telling you it's the wrong time. You only get one shot, so do it when you think you have the best chance of success."

Be overly prepared.

"You should know your product or business inside out."

Don't go into a pitch "not knowing everything there is to know about what they're pitching. You should be prepared to answer any question about it. Whether it's about finances, manufacturing, inventory or processes, you should know every single detail."

Be enthusiastic.

"Enthusiasm and passion are infectious. I've seen great pitch people that with sheer passion and enthusiasm convince people to buy or invest in things that they never would have under any other circumstance."

"I've seen the greatest ideas fall completely flat when presented by someone who lacks enthusiasm."

Related: Watch: Why Even Prepared People Don't Always Get a 'Yes' From a Pitch

Be likable.

"Remember if you're trying to convince someone to invest in you, they need to not only like what you're asking them to invest in and believe that it is a good investment for sound reasons, but they also need to like and believe in you."

"One of the biggest mistakes people make is not listening or having an arrogant attitude."