Letting go sounds passive, like giving up. It's the opposite. Holding on is the effort — the clenched, all-the-time labor of gripping a thought, a person, an outcome, a version of how it should've gone. Letting go is what happens when you finally set the weight down.
You can't force it. 'Just let it go' is useless advice because the grip isn't in your hands, it's in your believing — believing you need this to be okay. The work isn't to pry your fingers open; it's to question the belief underneath, until the holding stops making sense and the hand just opens on its own.
Try this: whatever you're gripping, finish the sentence 'I'm holding this because I'm afraid that if I let go...' — and look hard at the answer. Half the time the feared thing already happened, or never will, or wouldn't end you. The grip outlived its job.
Letting go isn't losing the thing. It's stopping the war with what already is.
Because under the grip is a fear, and the mind thinks holding on keeps the fear at bay. It doesn't — it just keeps you in the war. Name the fear, look at whether it's actually true, and the holding loses its reason. That's when the hand opens.