This is great article that gives some ways to look at a problem differently a second time.
“If you just guess answers over and over, they’ll be pretty similar to each other. After all, why would you guess anything differently the second time? So the technique is designed to make yourself guess the second time, almost as if you were a different person.Here are the instructions they gave:
First, assume that your first estimate is off the mark. Second, think about a few reasons why that could be. Which assumptions and considerations could have been wrong? Third, what do these new considerations imply? Was the first estimate rather too high or too low? Fourth, based on this new perspective, make a second, alternative estimate.”