My suggestion would be to read about Karma from trusted sources, specifically from serious Yogic teachings and/or western esoteric teachings like Anthroposophy (Rudolf Steiner).
And keep in mind that for most of us it is more than a lifetime process.
Based on advice I got from forum friends, then my experiments, I would also strongly recommend to play it with fields that keep you in balance : Essence of Shen, Love fields, Shatachandi Yagna, etc.