Make no mistake, baring your big idea on stage in front of an audience is no easy task--especially if you're being judged. And speaking for the judges, we can be ruthless.

Over the weekend, in a small, well-appointed and (thankfully) air-conditioned auditorium in Tony Hsieh's revitalized Downtown Las Vegas, seven judges, including yours truly, sized up nine companies from all over the country.

These weren't just average startups.

The companies, all founded by college students, had already won competitions that took place at seven universities across the U.S. This final round, was for all the marbles. It was hosted by the Mark Cuban-backed RECESS, a collegiate pitch competition based in Venice, California. The winner would go home with bragging rights for life and the chance to pitch to members of First Round Capital's student-led Dorm Room Fund, Lloyed Lobo from Sunnyvale, California's Plug & Play Tech Center and Andy White from the VegasTechFund.

We judges were asked by RECESS founders, Deuce Thevenow and Jack Shannon, to consider the startup's market potential, its ability to offer a clear understanding of the competition, and a list of other factors. But we all had our own internal grading schemas too.

Lobo was impressed by founder developers--those who can code, as well as launch. Judges from the Dorm Room Fund prized originality of idea. Their thesis: If there's considerable competition in a given market, you're going to have an uphill battle--and that's not something many VCs will want to get behind. Other judges were mostly interested in the strength of a company's founding team: Are you up to the challenge of starting a company? Do you have the support you'll need?

For my part, I was more interested in the softer elements of a person's pitch. After all, I'm all about story-telling and strategy. While mostly the startup founders who presented met my basic criteria with flying colors, I did notice a few behaviors (chewing gum on stage, etc.) that just about any entrepreneur worth her salt should avoid.

Here are four tips to help avoid those red flags:

1. Tell us about you. You're on stage and you don't have much time, but if I walk away either not knowing or not understanding where you and your product idea came from, that's a problem. The takeaway here: Articulate what your company is all about, and make me care in just a few short minutes. Believe me, this is tough. So practice.

2. Share the stage. Unless you're just a one-person show, make sure everyone on stage presenting has a role in your pitch. Even if one person on the team is clearly the better presenter, if you're on stage, you should say something. It's awkward to have someone just stand there.

3. Get excited. Besides being able to show early traction and a timeline for your company's progress, I wanted to see founders who could broadcast enthusiasm and the kind of eagerness that screamed: I'm thankful to be here and I'm the right (or better yet, only) person for the job.

4. Look the part. You're asking big-time investors to part with thousands or even millions of dollars, show them you're up to the task of running a company that will be huge one day. You must make a good impression. And while many founders can get away with wearing jeans, you should still look put-together. That means you should dress professionally, and whatever you do, don't chew gum on stage.