You usually come across concrete examples in stories about the souls in purgatory.
So-- for example-- suppose you had someone who was a very willful person, who committed a lot of sins through their selfishness. But then there are people in danger, and that person puts themselves in danger in order to help save them. Like, say, a drowning child. Or someone had fallen over a cliff and hurt themselves. Or there’s a great storm. So the selfish person forgets his selfishness, and puts his own life in danger to help/save that person in trouble. But suppose he fails, and he dies in the process. That act of sacrifice is viewed favorably— because the one act of genuine generosity counteracts the many acts of selfishness.
But that would be an extreme example. In most cases, it means to have a good heart, to love your neighbor as yourself, to love God above all other things… and if that’s your default attitude and mindset, much will be forgiven. Whereas a person who commits the same sins you do, but doesn’t have that loving/charitable attitude running at the same time, is going to have a harder time of it.