It may be difficult for you to be objective about the impact of your learning on others. Try to get the opinion of those on whom it was to have an impact. If this is impractical or impossible, seek the opinions of those who are in a position to more objectively observe your performance e.g. colleagues.

Don't passively wait for feedback. Seek it out. Feedback comes in all manner of forms. It might consist of a simple conversation, perhaps asking whether the advice you gave was useful. It might come in the form of performance appraisal or audit.

If you have not had a chance or were unable to receive feedback, then please state this.