There's a saying that I've been thinking about lately. I've seen various versions attributed to various sources, but they all go something like this: "Under pressure, you don't rise to the occasion, you sink to the level of your training. That's why we train so hard."
We strive to be fully in the room, mind and body, during practice.
We talk about a kata, we go over it step by step, we break it down, we look at it from a hundred different angles, we try bunkai, we repeat it. We do it over and over, thousands of times, to hammer into our subconscious and our muscles what we want to achieve with each move.
This repetition is a key element, but it is a particular type of repetition.
This isn't like when you're on the stair machine huffing and puffing, stepping over and over, but making your shopping list in your head at the same time. Though you want to get to a point beyond laboriously cataloguing each part of the move as you do it, your mind must still stay in the practice, in the dojo.
Our practice includes talking about the history, culture, etiquette, and philosophical underpinnings, and these aren't just extras; they are important to our understanding and ability.
When you're memorizing second kata, for example, take a moment to note who created it and for what purpose. Or when you're in the trenches of 2 years of naihanchi kata as a ni kyu and ik kyu, ponder the calligraphy pair of nin tai and sho jin and how these two qualities are helping you make it through this difficult training.
An assailant is unlikely to demand that you define maai, but understanding what it means and how we think about it in relationship to yakusoku kumite, for example, will matter.
When you commit to being fully engaged with your practice, you prepare yourself to act under pressure, whether that pressure is test day or an altercation where you need to defend yourself.