It has taken me 32 years to to learn this concept and I still don't have it down pat yet.
I have been an insecure person for the majority of my life...insecure with myself and my relationships with others. I constantly worried what other people thought of me and often got upset over things that really didn't matter.
So, now I'm learning to practice the concept of "letting go." I still haven't mastered the concept and probably never will completely. I struggle with insecurity one way or another every single day. In the midst of my insecurities, I also want to have total control of every situation. If I'm in total control then things can go the way I think they should go. No failure, no heartbreak and no unwelcome surprises.
That's not the way life works though. Even if I feel that I'm in control, life is still going to happen. I will still get hurt or disappointed. I will still sometimes fail, especially when I'm trying to control the situation.
For me, letting go just means realizing I can't control what's happening around me but I can control how I respond and how I react.