No one sees but you.

Skill improves or declines through repetition. Both quantity (how many + how often) and quality (how intentional + how good). That’s true of technical skills (piano, surgery, accounting, etc) and personal skills (courage, discipline, empathy, etc). 

When you get more reps, more often, at higher and higher levels, you give yourself a really good chance to become really great at any skill. We’re built to learn, especially through experience. One difficulty can be getting enough reps to embed and grow the patterns that make up your skill.

Two ways you can get more skill reps is through mental rehearsal and mental replay. Mental Rehearsal is when you envision yourself executing a skill in a future situation. Mental replay is when you remember yourself executing a skill in a past situation. 

Like live reps, quantity and quality of rehearsal and replay reps exert a significant influence on your skill development for better or worse. The difference is you’re always getting a mental rep even when you’re not getting a live rep and only you know what happens in your mental reps.

Discipline is the shortcut. Do the work.