I am studying for the NCLEX myself. I have taken extra NCLEX classes to help with test taking and understanding the information. The best advice I received was not reading too much into the questions! People have also advised me not to read actual "textbooks". It is too much information to recall. There are ATI books that summarize the information on a need to know basis. The Kaplan site and books are also a great resource.

I think the best thing you can do the day before is work if you can as a graduate nurse, keep busy if your state doesn't allow this, have a good nights rest and go in with confidence. My own experience was that way and I had no anxiety, was so tired from working that day, slept well and did very well the following two days on the exams. Of course my boards were back in the day there were two full days of testing. There were four of us, who drove down together. The two who chose not to work until after they took boards and studied both failed the first time. The two of us who worked, were tired and slept well did well.