I’ve learnt so much on how and when to buy but I lack the skill to sell. Drop your best advice for selling. Master thread!

Over my investing journey I’ve read a lot and learnt a lot about investing. It generally revolves around when to buy and how to buy. I’ve had some good companies that I invested in and have had some good runs. But ever sell transaction is a regret and stressful.

I’ve sold when PE is higher than average
I’ve sold when my thesis is complete
I’ve panic sold
I’ve sold when another opportunity comes up
I’ve sold to rebalance
Etc
Etc

But every time I sold, I have seen that it was most likely a premature sell. Markets kept going up, stocks kept going up. Sometime I have regret. Some I’ve been lucky to sell before they crashed. I feel like i lack the skill to sell.

I see so much discussion on buying but I hardly see anything on selling. Can you drop your best advice here so that I + we can learn?