yesterday i took the JLPT (N2 level). my advice / experience:
• study so that you could clearly pass N1 if you're taking N2. in particular, make sure you can understand formal nonfiction (newspaper articles, modern-history texts, business-anything) in both spoken and written form EASILY. you want to be at the point where you can VERY EASILY read all kinds of NONFICTION, adult books in japanese. you should use an app like "mazii dict" (dictionary where you can easily read news blurbs inside it) or "mondo" (purely intended for reading news) to read some news articles every day.
• instead of (panicking and) re-reading the long reading pieces, read and answer each question SLOWLY. once slowly saves time and comprehension, versus thrice fast.
• work on memorization techniques for when listening to conversations. just youtube "memory champion" etc and you'll see what i mean. you can reread text, you can't replay audio.
• if watching anime to learn, i'd say watch it once with japanese subs (looking everything up) and then once without subs. i didn't realize how much i was still relying on subs for comprehension of high-level stuff until the long listening came. (vlogs, "let's learn japanese grammar!" and other everyday stuff i'm understanding just fine without subs).
• it's very important to remember, on the JLPT there's basically NO CONTEXT for anything. obviously this makes things a lot harder than normal reading/listening.
——— ( my study / experience under the cut! )