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Barbara Corcoran of "Shark Tank" on how to get a bite

Barbara Corcoran is a SINO—shark in name only.

"I'm actually quite a pushover," she said. "But I drive hard, so sharks keep moving forward."

As hard as it may be to imagine the show without her, she almost didn't make the cut. In her autobiography, "Shark Tales: How I Turned $1,000 Into a Billion Dollar Business," she revealed that Mark Burnett had chosen someone else to be the first female shark. Most people would have left it at that, but Corcoran isn't "most people."

"I collected myself, reached for my keyboard and banged out my response to Mr. Burnett," she said, recalling the three reasons why he should enlist her.

  1. "I do my best when my back's against the wall."
  2. "If you have both ladies in L.A., you can mix it up a bit."
  3. "I'm just as smart and mean as the next guy."

Needless to say, she proved persuasive, and she has been a part of the show ever since. She keeps coming back, too, because she never knows who's going to walk through the door.

(Read more: When a shark doesn't pay up, an angel investor flies in)

"There was the guy who said he would turn pure salt water into pure gold if only we'd give him a million dollars to build his first tower," she said. "And then of course you had the bluetooth guy, who said you had to surgically put the device into your ear. Someone asked, 'Hey, what happens if the battery runs out?' You surgically remove it and recharge it."

Though they may fight each other on television, she revealed that there's more to the onscreen relationship than it may seem.

"I think a lot of people feel that the sharks don't get along," she said. "And on the set of course, if that shark stepped in my business, I can't stand him. But the minute the deal is done and we get on to the next deal, we actually have tremendous respect for one another."

So if you're an entrepreneur hoping to get into the tank, pay heed to her words.

(Read more: My office was a trailer: Start-ups that started from nothing)

"Listen, when you're on 'Shark Tank' with your little business, BAM ... the business explodes. It's like you're sprinkled with magic dust. You're found by every big store, they're calling you. The same guys you've been calling for months that didn't return your calls, the investors you pitched that had no interest in your business now all want to buy in. ... It's almost hard to fail if you're brought on 'Shark Tank.' "

—By Liza Hughes, Special to CNBC.com.

Tuesdays have more bite with back-to-back episodes of "Shark Tank" on CNBC every Tuesday night.