Ask YC: Got a YC interview invitation, now what?

My co-founder avk and I just got an invitation to interview for this round of ycombinator for our startup called Outspokes. We're both really excited at the opportunity and don't want to screw it up. There was a thread earlier from DirectedEdge about their YC interview (http://news.ycombinator.com/item?id=923722), and it emphasized that a strong demo would be helpful. What are the experiences of other current YC companies? For people who interviewed in previous years but didn't get accepted, what would you have done differently? I'd love to get everyone's opinion on what we've built so far too. http://outspokes.com/ If anyone works at a web consulting firm or does freelance web work, I'd like to talk to you more about how to make our product fit your workflow. Shoot me an email at jerry(at)outspokes.com or leave a reply.