Japanese Guide
Japanese Guide
新明解国語辞典 (Google Play) (Apple Store or via Dictionary) [paid]
You should make it your goal to move from an E-J dictionary to a J-J dictionary as fast as possible. The most important thing that a J-J dictionary does is allow you contextualise Japanese in Japanese itself, this means that your brain creates natural and correct linguistic associations. In turn, you become more fluent, and pre-existing concepts you hold are solidified and expanded on simply by learning new things (win-win).
You should also be avidly using the example sentence finders. This not only helps ingrain rules on how to use grammar or words, but allows you to stumble on nuances and patterns relating on usage that aren't taught in textbooks and can only otherwise be learnt through extended exposure. Unfortunately Google Ngram doesn't work with Japanese (yet?) but if you need to check whether your sentence structure is natural (or at least, understandable) then giving it a quick google search to check if natives have used similar structures is your best bet (but please note, this isn't fail-safe). Finally, pulling out the old search tricks:
「〇 と 〇 の違い」for the difference between two words/kanji
「〇 とは」or 「〇 の意味」for blog-style explanations
「 〇 の使い方」for blog-style commentary explaining use (particularly useful for concepts that even Japanese people struggle with such as ビジネス敬語)
ッツ Ebook Reader (Browser Reader)
Reading is undoubtedly one of, if not the most effective way to increase your Japanese ability because of the sheer amount of native-level content you can consume in a short span of time. Reading can be in many forms, so whether it's novels, light novels, news, or message boards, please read. For message boards and news links, see below.
For a guide on how to set up flashcard card mining, refer to Anki Guide.
Genki (げんき) (N5 - N3.5)
Tobira (上級へのとびら) (N3 - N2.5)
新完全マスター (N4 - N1) personal recommendation
みんなの日本語 (N5 - N2)
The textbooks on the left are likely to be series. The JLPT level assessment is based off completion of the whole series and is a subjective opinion based on my experience and online perspectives (if I have never used the textbook).
To be frank, you don't need to install an anki deck, or spend years writing out all the kana. Just watch one of the thousand videos on youtube on them, write them out a few times, then hop straight into one of the online quizes (I like Real Kana), and begin drilling. You should aim to get these mostly memorised within a few days, and then move on to the next step of your Japanese-learning journey.
Anki (Flashcards) You should use Anki - refer to Anki Guide
Yomitan Recommended - Hover-over dictionary extension
For setting up Yomitan and more information, please refer to the main Github page. Its main developers are active in the TheMoeWay community if you have issues or need help.