How Do You Apply Knowledge Under Pressure?

Being good at applying a skill under pressure doesn't happen by accident. Back then, the only way you could learn was going to the gym really and learning directly from your instructor because there wasn't many books or videos. The idea was just do it, you know, it doesn't matter what you do as long as it works. And also the teaching style back then because it was so much focus on competition. But nowadays is much easier. I think people are getting better or getting their black belts faster than they were before.