The review books and mock tests are a good way to measure what's lacking in your current knowledge.
I used review books a lot during my review, and I really think I COULDN'T have passed the test without using them, given the short 4-month review period on self-study during weekends.
I'm including the affiliate links to Amazon if you'd like to buy these recommended,
tried and tested review books.
1) JLPT N3 mock tests and strategies. A very good book, I just answered all the sample test questions and read all the answers and explanations. make sure to answer the 1st mock test at the start of your review, and the second one near the end of your review to gauge improvement.
Great practice, I can even say THIS IS THE book that made me pass the exam.
2) JLPT Kanzen Moshi N3 w/CDs [Japanese Language Proficiency Test- If you can
answer the questions here with at least an 80% score, I'd say you're practically guaranteed to pass!
The next book, or book series is....