Reflecting on the grade that you received on a recent assignment, rereading the feedback you received on it, and considering the steps you could have taken to make it stronger are all part of development and improvement.
When you rationalize the aspects that you could have done better and think on a better way to do it, you understand and internationalize the concepts you are working with and you get ready for making it much better the next time.
The understanding of previous mistakes is the key in the learning process.