You should sum up your experience and write down what you did wrong every time to see why you did it wrong. Just pay attention next time. You should remember that you are not as smart as others, but you are not as serious as others. Maybe you did it without seeing it clearly, or maybe you didn't check it carefully after you finished it. Check is not recalculation, but calculation. If you recalculate, you may make mistakes, and it is easier to find mistakes in the calculation. I hope these words can help you.