Past Rice Business Plan Competition victors dish on when to ignore the judges, how to pick investors, and what to do after you go home.

By Anne VanderMey

FORTUNE -- The Rice Business Plan Competition is underway in Houston, where 42 hopeful entrepreneurs are going head-to-head for $1.2 million in investments and startup cash. A few former winners have sold their companies for big sums: "I'd never seen so many zeros," joked Nicholas Seet, the 2005 winner whose company went to Adobe (ADBE) for more than $100 million. Seet and a few other former Rice contenders talked during the competition about what they learned while pitching at Rice, and how those lessons have applied to running an actual business. Here are a few of their tips:

Be prepared for everything to go wrong

Technology often fails just at the moment you need it most, but that shouldn't faze the seriously prepared presenter. Last year's winner, NuMat Technologies, used a lot of videos, which are particularly prone to technical difficulties during a presentation. To make sure it all went according to plan, NuMat CTO Chris Wilmer says he went around to all the practice rooms beforehand to test the video equipment. A Rice judge remembers seeing a presenter who took it a step further and actually brought a stack of poster boards along bearing makeshift PowerPoint slides just in case the projector failed.

Sometimes you need to ignore the judges

"Don't take anybody's advice instantly as you receive it," says Jenny Corbin, CEO of TNG Pharmaceuticals, the 2011 winning team. Just because one judge says it, "it doesn't necessarily mean that that's what the audience is looking for." Instead, she says, "look for trends and follow trends, not the oddity."

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Sometimes, it's impossible to take all the direction you get: "Eventually, the advice will conflict [with] other people's advice," Seet says. "And that's when you know you're where you want to be." He added: "Half the judges liked the name Auditude and half the judges hated the name Auditude. That's when we knew we were just right."

Don't get too attached to that business plan

A plan that goes over well at Rice may not be perfectly suited for the marketplace. "Judges are one thing, and customers are totally different, and you gotta listen to the customers," says Seet, who radically changed his business model after his victory at Rice. "Everything was wrong!" he says. Seet says he switched directions more than once: "You can't be so stubbornly married to that plan."

Business plans are notoriously subject to change between the classroom and the real world. "You might as well throw your business plan out the window," Corbin says. But, she adds, "Walking out of the door here as a winner, which is fantastic by the way, you've got the backing and the expertise to help you make that business a reality."

Connecting with judges and other teams is arguably the most important part of Rice's competition. "Winning isn't a guarantee of success and losing isn't a stamp of failure," says NuMat's Ben Hernandez. Just ask BlackLocus. The team didn't make the final round when they competed in 2011, but they picked up key investors at the competition and sold the business to Home Depot (HD) in 2012.

Business plan competitions are hard, entrepreneurship is harder

You must be fanatically devoted to your startup. "I thought that after graduation, being able to focus full-time on the business, it was going to get easier," says BlackLocus's Rodrigo Carvalho. "No! It just gets harder from there."

Pitching a group of investors gets easier, Seet says, because you're used to working a big room. And there are some pretty great highs. Andrew Smith, CEO of ATDynamics, remembers when his business went from having sold six models to logging a 3,500 order. "That was a fun day for me," he recalls. "The engineers went nuts, but I had fun."

Still, "for every amazing moment, there's a moment of 'Oh God, we're all gonna die,'" Seet says. "It takes a lot of chutzpah to continue and still be able to sleep at night and maintain the relationships that are technically more important than that big exit."

Choose your investors like you'd choose your spouse

Investing partners come in all shapes and sizes. Not all are created equal. "Just be very careful who you take money from," Seet says. "It's a relationship just like marriage." You should be in the same boat to either success or failure. "They need to be standing by your side," he says, "and that relationship doesn't happen with every investor."

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Carvalho says he met two VCs at Rice who were pivotal to his company's success. "It's not just the money that you're getting," he says. "You should be looking for investors that can help you."

Some investors act like helicopter parents, while others allow more independence. "If you can find the angels that have built companies," Smith says, "and understand the volatility and the roller coaster [of entrepreneurship], those are phenomenal people to team up with."