Sometimes, we tend to forget to use our own knowledge, intuition, and reasoning to take the right decisions. This is what we must try to avoid doing, instead make use of your own skills and tools to assess the best desicion with all the factors taken into account. Having said that, it's still not bad to do mistakes once in a while, as all people do. What's important is you learn after you failed, and use that learning you gained to perform better in decision making.

Learn from your mistakes, and do not get stuck in the past. Move forward and be better.