Work on memorizing basic info that you will need forever---normal lab values, vital sign parameters, medication classifications, etc. This is stuff you absolutely have to know, no matter what setting in which you plan to work.
Other things you will have to learn on the job, like the previous posters said. Time management, organizational skills, prioritization, emergency procedures, etc---that can't really be memorized; it comes with knowledge and experience.
Be humble; no one will expect you to know everything. If they do, they suck!
You will make mistakes; that's inevitable. Learn from them and become the best nurse you can be.
And remember, the "real world" is gonna be so much different from the school and NCLEX world. But that's okay.