Someone who achieves great success is always improving, "whether it's their career, project, product, or service." Continuous improvement means getting good at something, then getting better, and then aiming to be our best.
The old saying goes "practice makes perfect," and repetition was a key part of legendary basketball coach John Wooden's philosophy.
It's also important to focus on your strengths rather than your weaknesses. It's fine to be bad at a lot of things, - as long as you're really good at one thing.