From time to time, I found lots of sources, stressing about the importance of "letting go". This is healthy, not only from the perspective of spiritual development but, if you're not into that, also from the perspective of a balanced mental life (and in the end, they amount to the same thing).
What most sources almost never tell you though, is how you go about it.
So, here it is, in all it's apparent simplicity:
The secret to letting go, is realizing you don't need it.