The split second thought that popped up into my head was evil and good only have the power you allow them to. But I completely disagree with that statement. I don't really believe humans can be truly evil or good. Everyone, regardless of what they've done in the past has the capacity for doing good an bad. We all have sides of us that speak good to us, encouraging us to be kind and sensitive. And we have a side that eggs us on to do bad, it tells us to think selfishly or twists our beliefs into thinking something evil is actually good. Call it a conscience or shoulder angel, whatever. I don't really think of it as conscience, because it doesn't necessarily tell us what's right or wrong, it just tells us to do something that could be good, or tells us to do something that could be bad. Now that aside I do think actions can be good or evil. I've experienced the results of other people doing evil things. I was sexually abused and to say that only happens because it's allowed to is not only victim blaming but it's unrealistic. Terrible things happen to everyone even when you strive to be the best you can, it's part of life. But does every situation have to have the worst possible outcome? No. And we only have control over what happens to a small degree. So what do you do when you feel that evil is reigning? You hold onto what innocence you have in yourself. It's kind of like remaining positive in a negative situation, but it's so much more than just being positive. I don't think it's possible to be 100% positive, even the most happy of people get dragged down. Yeah it sounds kind of hopeless. But humans are also very good at finding the light hidden in the shadows. What do you view as good and innocent? How can you amplify that little bit of good and put it inside you? I think those are questions with answers unique to the individual. It helps if it's something a bit more tangible than emotions and thoughts. I'll use me for example. I love animals. I look at my pets and I see very good living things. They are sweet and sensitive and (adorable) caring. Their simple nature means that they've always been that way and will always be that way, playing with them creates, even if only temporary, a really good escape. So I guess the actual answer that I'm trying to give is that no, evil is not more powerful. Good and evil, I believe, are on equal grounds and both exist everywhere, it's your choice whether you ponder over which. No that doesn't mean focusing on one will make the other go away. The thoughts we have are pretty powerful and in the very least when you're stuck in the bottom of the bottomless pit that something good will makes trying to climb out seem a lot easier.
Rereading that I'm not entirely sure if it was helpful, but those are my thoughts.