Who do you think could create a better story on the spot: you or Shakespeare? Ignoring the fact that good ol’ Bill has been dead for some time, in his life he had a lot of practice creating metaphors. All of that practice helps him as a storyteller.
Similarly, if you want to use metaphors to cut down your studying time, you have to practice. You have to make finding metaphors to lock in ideas a habit. If you are curious about building storytelling techniques into your studying I recommend taking on a short and simple 2-week challenge when you start hitting the books again: