BOOKS FOR EXAM REVIEW.
If you want a more focused study for the exam itself, after you've learned your Japanese, you can try the sample questions in the official JLPT trial exam books or here if you're in JAPAN.
If you prefer sample questions with explanations included in the answers, you can try one of the exam preparation books which have lots of drills and tips. Do you need an exam prep book? Maybe not, but it'd surely make things easier (at least for me, it was a big help).
You get very good practice from these books, getting you to a better prepared, more confident state.
- Nihongo Challenge Grammar Bunpo N4, Nihongo Challenge Vocabulary Kotoba N4, and the Nihongo Challenge Kanji N4-N5 - one book for each skill area. Try testing yourself in your weaker skill. Time yourself while answering the test questions. Good for testing yourself.
- Kanzen Master for N4 JLPT Grammar Bunpo - I've used the Kanzen master for N3 and really, really enjoyed it. It's a good thing there's a version for N4, lots of drills and explanations -- really useful for self-study.
- JLPT Kanzen Moshi N5 and JLPT Kanzen Moshi N4 (99 pages), and the Tanki Master Nihongo Noryoku Shiken Drill - complete reviewer for grammar, reading, kanji, listening (with CD) JLPT N5 version and the Tanki Master JLPT N4 version (73 pages) - all complete exam drill bundled with CDs for listening. Use this as your final practice if you like a week before the test for some final brushing up.
- And lastly, the Unicom series - these have had very good recommendations for years from a lot of people. However, it does not include listening CDs, but the reading selections are good, very much like the exam. There's the Preparatory Course for JLPT N5 Reading. the Preparatory Course for the JLPT N4 Character & Vocabulary & Grammar & Reading,
- Go ahead and prepare yourself for the exam! :)