I can see two ways of finding partners: 1) Your existing social circle 2) Networking with like-minded strangers at meetups/community

Regarding, 1, not everyone in a social circle can A) add unique value, B) be in a position to take on the risks, or C) desire entrepreneurship, perhaps being a better first employee

As far as networking approach, having a good partnership surely would increase % of success. But a partnership made in haste with someone you might hardly know will surely increase the chance of failure even more so.