My recommendation would be to go through the question pool once per night and write down the questions/answers you got wrong. After about 1 week you should be getting most of them correct. Ones you keep getting wrong read the description really well or ask someone if they can explain the question a different way.
The NAR 1 jr exam is pretty straight forward once you understand rockets but the 88% passing score means you really need to know it well.
If there a few you have a hard time remembering you can review those right before taking the test.