Getting into a top-tier accelerator like Y Combinator or 500 Startups can be an amazing breakthrough for your business, but getting to all that juicy mentoring and exposure means making it past the interview stage.

What are the panelists who will speak with you looking for? What turns them off? What excites them? Knowing this sort of thing beforehand would certainly be a leg up for your team, and that's just what a recent post on the 500 Startups blog by venture partner (and YC alum) Andrea Barrica offers.

To make sure accelerator applicants aren't going into their interviews blind, Barrica gathered an impressive panel of accelerator alums, offering mock interviews to participants in General Assembly's accelerator prep program and sharing the lessons learned publicly for the benefit of the whole startup community. If you're hoping to be facing a panel of partners soon, the entire post is definitely worth close study, but to get you started, here are a few of the most common errors Barrica and her fellow mock interviewers noticed.

1. Talking too much

Whether it's nerves that make you a motor mouth or just enthusiasm for your business, Barrica and the rest of the assembled experts suggest that you get your urge to overtalk under control. "Over-explaining product, technology, everything. Tangents. Doing a full sales pitch," this type of misstep was the most common, according to Barrica, who reminds founders that the purpose of the interview is "getting people excited about your business, not trying to sell them your product."

2. Getting defensive

In order for a founder to get something out of an accelerator, they need to be coachable. Therefore, being defensive in your interview is a grave sin. To succeed, you need to react positively to pushback and demonstrate your calm both verbally and nonverbally. "Confronted with a tough question or interviewer, many people become visibly stressed, nervous, verbose, even angry or hostile--their postures change, their voices speed up, and they over-talk and under-listen," Barrica notes.

3. Co-founder tensions

You and your co-founder are going to go through A LOT together as you build your business. You really should be able to work together to successfully handle a short interview. But according to Barrica, strange co-founder dynamics were actually a pretty common pitfall in the mock interviews. "Nothing worse than seeing co-founders disagree, interrupt one another, or have one founder completely dominate while the others sit in silence (looking at you, 'CTOs')," she writes.

How can you avoid these problems? Check out the complete post for tons of advice on acing your interview.