My process has been and will always be know why you own it, and if that changes, sell it.
It sounds simple, and I guess it is in a way. But it is the easiest way to navigate your holdings and decide what to buy more of/move on from.
Where a lot of people get caught up and make mistakes is their thesis tends to be "I don't want to sell in the red" or "I'll sell when it gets back to even". This is disastrous. You are not basing your decision on anything to do with the company, just the share price. And, shares can deviate from logical prices for long periods of time. Case in point, when I accumulated Aritzia when it went from $50 to $20 in 2023.
Had I used price as my main focal point, I likely would have sold. Instead, my long-term thesis of Aritzia being able to get into the US market and expand rapidly was still in place and 2023's issues were nothing more than a mis timing of inventory ordering.
For every single stock you own, you should have a thesis. Why you own it. Maybe it's for the dividend, or maybe you believe the company will continue to grow at a double digit pace.
An example, I could go back to Aritzia. You like Aritzia's US expansion, for example, and that's why you own, it should lead to strong returns.
You then see that US expansion slow down. Now, you have a basis to go off of. Is this thesis breaking? If it is, you sell.