I have studied Japanese roughly a year and I took JLPT N3 this month. Although the result has not been announced yet, I'm optimistic that I can pass the test. But here's the weird thing: I really can't speak well or write Japanese well. I can understand reading or listening (not the complicated one. TV news is still too much for me. TV shows more like it), but speaking or writing... Maybe that's because I learn Japanese by myself. I studied from books and online audio course. I guess passing a test and doing real communication in real time is really a different thing. That's why I'm trying iTalki now. I went through the basic again with my sensei(s), but I couldn't help it. My speaking skill really is that bad. If you want to pass the test, there are a lot of books designed specifically for that. I studied a lot from that kind of books (I guess it will be different if it was for N2 or N1 since the exam structure also a lil bit different and the books that cover that is more little).

I mostly self teach and learn through conversation with friends so I am not sure how many hours I have spent learning Japanese, but I have been learning Japanese for almost 4 years now. Also I passed the N3 level last year If you are new to it, I suggest learning Hiragana and also Katakana for a starter. Don't forget some basic grammars and words. Once you get a hang of how the sentence works, start working on your listening and speaking. Hope this helps!