Karma in simple words "is getting what you give" or reaping what you sow . There's good and bad karma but i think for you or anybody to really feel the effects of karma has to know what is right from wrong and people have a different ways of thinking and values. What might be right may be wrong to someone else, this is why life is confusing the negative force in the world cause us to question our purpose and why we are here if God is so good why do bad things have to happen. You can prevent bad karma by not associating with bad people or people who provoke you, because their toxicity can cause you to take it out on someone else usually someone that they feel is weak or if you are kindhearted person who doesn't have the heart to hurt someone it can drive you crazy slowly but surely to the point you'll lose it or think of suicide when it gets to be too much but most people turn to drugs or something else as an alternative to just ending their life. I would know cause if you stoop to their level and you know better you can bring bad on yourself. My mother toxicity caused me severe stress. And hanging around bad people you will begin to mimick them and do the things they do. So mediate, and be peaceful, and resilent but still stand up for yourself. You have to learn how to control your tongue and and anger, never fall prey to that eye for an eye trap. Your life will always be in a shaky state