Standing in front of the crowd without feeling the pressure.
Public speaking is not my natural talent. When I decided to improve this skill, I did tons of research. I read about various advanced techniques to handle pressure. Unfortunately, nothing worked for me - I still felt nervous and struggled during presentations.
A few months ago, I was invited to speak about IoT at some conference. The planned presentation should last only 12 minutes. That is when I realized that I have to prepare HOW I want to talk about the topic.