Demosthenes, the greatest orator in ancient Greece, did activities designed for improvement.

• He studied a lot: law, philosophy, and great speeches and acting.
• To get rid of the habit of involuntarily lifting his shoulder, he practiced his speeches in front of a mirror, with a sword suspended from the ceiling so that if he raised his shoulder, it would hurt.
• To speak more clearly despite a lisp, he went through his speeches with stones in his mouth.
• He built an underground room where he could practice without interruptions, but since courts at the time were very noisy, he also practiced by the ocean, projecting his voice above the roar of the waves.

This involves breaking down abilities into component skills, being clear about what subskill we're working to improve, giving full concentration to a high level of challenge outside our comfort zone, just beyond what we can currently do, using frequent feedback with repetition and adjustments, and ideally engaging the guidance of a skilled coach, because activities designed for improvement are domain-specific, and great teachers and coaches know what those activities are and can also give us expert feedback. 

• Nurture the growth mindset: Believe and understand that you can improve.
• You must want to improve at that particular skill. There has to be a purpose you care about because it takes time and effort.
• Know how to improve, what you can do to improve, through deliberate practice.
• Be in a low-stakes situation, because if mistakes are to be expected, then the consequence of making them must not be catastrophic, or even very significant.

We spend so much time in the performance zone because most of the time our environments often are, unnecessarily, high stakes. But there are still things we can do about it:

• We can create low-stakes islands in an otherwise high-stakes sea.
• We can execute and perform as we're expected, but then reflect on what we could do better next time.
• We can lead and lower the stakes for others by sharing what we want to get better at, by asking questions about what we don't know, by asking for feedback and by sharing our mistakes and what we've learned from them.