Letting Go

It's funny how this word keep coming up every time I come across something.
Even my damn blog has this on the side,  
"The best way for you to solve a problem is to LET GO OF IT"
Like seriously?
It's right to my face!

Seriously how does one learn to Let Go?
Is there a way? Or a formula to do that? Or do you have to go through certain things to even have a shot of learning something like that.
Sigh.
I hate that I care so much sometimes.
But then again, caring about others and things, is what made me who I am today.
To tell me to not care so much about others and things after living like that for 10 years or so, how does one change that?
Someone...please teach me "The Art of Letting Go".
Sigh.