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:
Once a day, every day, for the next two weeks, pick at least one idea, formula or concept from your studies.
Write out that idea on paper and break it down until you can see it in front of you.
Then time yourself to come up with as many possible metaphors for describing the idea or part of it in the next 3 minutes.
When metaphors happen automatically, any ideas you encounter become easy to remember.