YC founder here from S20 here.

The co-founder search is difficult if you have nothing interesting to say and if you aren't prepared to make the jump.

After my personal journey for 2 startups, (both venture backed and non-venture backed), I find it's important to: 1. have at least 2 years of personal savings ready 2. know what things you're exceptional at doing and what things you really suck at 3. be ready to bare all in terms of personal/biz life goals and transparency with your co-founder 4. proactively go to places where you and your co-founder would both enjoy doing (hackathons, startup events, conferences, online forums about startups, etc.) 5. have a "trial" period, where you make things together or work on the startup together with set milestones in mind 6. be ready to challenge a co-founder's ideas, be weary of people who agree with you 100% of the time 7. Not everyone has to be the "visionary" founder, some people are looking to join an existing idea and that's equally as important