If you seek improvement, learn to seek guidance and accept correction.
Improvement is a process that requires knowing where you are, what you have achieved so far and where you want to go, what you want to achieve in the future. Progress, as a fundamental part of improvement, is quite complex and many times the picture someone has of their progress is wrong or not enough to show them the next step.
An athlete needs people around him to remind him of the goal and show him the way in those moments when he feels that he has lost it. He needs people with experience in their subject matter who will see from a different perspective what needs fixing and present him with problems or solutions that he might not have thought of on his own.
All one has to do is listen positively to what their coach or partner has to say and be receptive to criticism that can make them better.