My approach is not too dissimilar to that of @dragosMLT
If a stock increased to too highly, I often sell all of it, or most of it. I try then to leave that money in Freetrade and not instantly buy something else. This stops me feeling like a day trader and trying to beat the market.
If I missed selling at an overvalued price, then I missed it and just keep the stop.
I try to look around the 15% mark and my research to see news articles and historic prices to see any indication of a rise that much is often fruitless. This determines if I sell in full. If there’s some news, I will often still sell most but it depends on the type of information I find.
Profit is good, but don’t chase it in the short term. I also live by the mantra of “you only lose money if you sell at a loss” and I try to use that to keep a position unless it’s rising unusually.