self study, where to begin?

I want to learn Japanese as efficiently as possible. I have already memorized all the hiragana and katakana, but my reading speed is a bit slow. Conversation-wise i know the basic greetings, expressions, and a lot of slang. My pronunciation is good. I just picked up most of what I know from my japanese friends and gfs, and from living in japan for a couple of months. I can get around japan by myself ok.
Now, I am not sure where to begin my self-study. Should I begin by learning the basic Kanji? Verbs and conjugations? adjectives? nouns? My aim is to be able to converse, as well as understand conversations. Perhaps I should be memorizing a couple Kanji a day while studying other areas? I will be returning to Japan soon, and perhaps look for a job handing out tissues and build my way up.
Your advice is GREATLY appreciated

Assimil

You may try the Assimil books for Japanese. It's good, but since you can already read the kana, you may feel slightly hindered by the excess of assistance the books provide by using romaji along with Japanese writing (Kanji and kana) as well as the pronuciation. Book 3 is a collection of 926 Kanji characters plus the texts of books 1 and 2 written in Japanese only. Speaking here of the French version, but I think that the English version is identical.

Genki Volume 1, if you want a Kanji book to accompany, P.G. O'Neill's Kanji book is what I use--except it's all in romaji and you may not like it too much.

Excepts of Genki are littered in https://jref.com/showthread.php?goto=newpost&t=40143