What hard skills did you learn as a founder?

I'm a co-founder with a business background. Initially, I was a bit bummed that my involvement in the product was limited to researching and building feature lists. To speed up the shipping, I learned some design basics. A little bit of Figma and Webflow. So we can ship together — I draw new staff, and at the same time, CTO builds. Closing the gap :) What about you?