Private
I see. Perhaps the Force isn't as universal as the Jedi teachings led me to believe.
It depends on the individual and their thoughts, fears, and strengths. There's no perfect method. I don't know who told you that, but they're wrong. There were a few stories in my time of Jedi of old who fell and found redemption. They usually become hermits or wanderers and renounced violence. The point is most see no reason to return to the Light after they gain so much power through the Dark...
My best advice is to remain watchful and make your own decisions carefully. The Dark feels different. Consuming and close at hand, rising when you need it most. You'll lash out at others. Instinct and emotion are all that matters in those moments. My master said it was an easier path for that reason. If the Dark Side traps you, unfortunately it may be too late to escape.