Twice a year, I get a ton of cold emails asking some version of the following question: how can I do well in my Y Combinator interview?
Rather than try (and fail) to respond individually, I put together the following best practices document, based on my experiences as a YC alumnus and former partner.

YC has evolved – a lot
Thirteen years ago, I walked into my Y Combinator interview with founders Paul Graham, Jessica Livingston, Trevor Blackwell and Robert Morris.

A lot has changed since then. Back in 2005, when I interviewed during the first-ever YC batch, it was very technology-focused. There wasn’t as much of a focus on business or monetization. Our 40-minute interview for our AJAX calendar website Kiko was primarily spent debating with Trevor Blackwell and Robert Morris on whether client-heavy javascript apps would become mainstream or not (turns out we were right in the end ;)).

Fast forward to 2018 and YC is a well-oiled machine. Over 1,900 companies have gone through YC, giving the partner team a generous sample size to identify positive and negative traits in early-stage companies. You can’t get accepted into YC solely on the premise of your idea; you need to convince the partners that you are amazing founders who can build a large business.
There are a lot of technically-focused guides on YC interviews, like Yuri’s at Hackernoon that I highly recommend. As a 3-time alum, former partner, and someone with close ties to the YC community today, I’ve seen the best and worst and wanted to share my own perspective.

Get these 3 things right
Later on, I’ll share some prep tips and more specific interview advice. But first I want to convey the three factors that will make or break your interview. If you take anything away from this article, it should be these three things!

1. Know what you’re doing
The most important outcome of your YC interview is to convince the interviewers that you are a great founding team. How do we judge that? Through a short, 10 minute interview, we make a judgement on the founders primarily on the confidence they project, and their expertise in their industry. You can demonstrate this in two ways.

Know your business inside and out
You don’t need to know all the answers to every question, but you want to show that you’ve explored every pathway in the maze of your space. Balaji Srinivasan’s concept of “the idea maze” describes what you want to convey.
When I was a partner, I’d often fire off questions like “have you tried [growth channel]” or “what about building [feature].” There’s only so much you could have done to that point, so the answer didn’t always have to be …